9 Substitutes for Onion (for Raw, Cooked, and Caramelized)

The recipe opens the way half of all recipes open — heat the oil, add one diced onion — and there is no onion in the house. Or there is, but you cannot eat it, which is a different problem with a different answer.

Onion is doing three jobs at once, and that is why it feels hard to replace. It provides bulk (a cup of soft, sweet vegetable that gives a dish body), aromatic depth (the savory background you notice only when it is missing), and sweetness that develops as it cooks. Most substitutes cover one or two of those. Almost none cover all three.

So the right pick depends less on what you have and more on what the onion was going to do — sit raw and crunchy in a salsa, melt into the base of a curry, or slowly caramelize into jam. Here is what actually works for each.

The Quick List

• Shallots — the closest all-purpose swap; works raw, cooked, and caramelized
• Leeks — sweeter and gentler; excellent in any cooked base
• Green onions (scallions) — whites cook like mild onion, greens finish raw
• Onion powder — flavor without bulk; for sauces, rubs, and dressings
• Dried minced onion — rehydrates into something with actual texture
• Fennel bulb — allium-free, sweet, and caramelizes beautifully
• Celery — covers the savory base and the texture, not the sweetness
• Chives — raw finishing only; add off the heat
• Asafoetida — a pinch of allium-free savory depth; the low-FODMAP workhorse

The One Measurement That Makes This Easy

Nearly every swap below is anchored to the same number: 1 medium onion is about 1 cup chopped (a tennis-ball-sized onion, roughly 5 to 8 ounces whole). Recipes say "one onion" and mean anything from a golf ball to a softball, so once you are substituting, measure by the cup rather than by the unit. It is the difference between a swap that lands and one that quietly doubles your aromatics.

Shallots

• Swap: 1 medium onion → 1 cup chopped shallots (about 3 to 4 medium shallots)
• Best for: Just about everything — raw in vinaigrettes and salads, cooked bases, pan sauces, caramelizing
• Skip it for: Nothing, really. The only real objection is cost and the peeling
• Health notes: Still an allium, so you keep most of what onion brings nutritionally

Shallots are the answer when you want the swap to be invisible. They are milder, sweeter, and a little more refined than a yellow onion, with a garlicky edge that flatters rather than intrudes. Raw, this is where they genuinely outperform the original — a minced shallot in a vinaigrette gives you onion flavor without the sulfurous bite that makes raw yellow onion take over a salad.

Two practical notes. They are smaller, so measure by volume and expect more knife work. And they contain less water and more sugar than a yellow onion, so they brown faster — drop the heat a notch when sauteing, or you will find bitter brown edges before the middle has softened.

Leeks

• Swap: 1 medium onion → 1 large leek, white and light green parts only, about 1 cup chopped
• Best for: Soups, stews, braises, risotto, quiche, anything with a slow cooked base
• Skip it for: Raw applications — leeks stay fibrous and grassy without heat

Leeks are what onion would be if it were polite. They melt into a silky, sweet base with none of the sharpness, which is why they are the backbone of potato-leek soup and vichyssoise rather than an understudy. In a long-simmered dish, most people would not identify the swap.

The one thing you must not skip: leeks grow in sandy soil and trap grit between their layers. Slice them first, then swish the pieces in a bowl of cold water and lift them out, leaving the sand behind. Rinsing a whole leek under the tap does nothing. Also note that leeks cook faster and more delicately than onion, so give them a few minutes less.

Green Onions (Scallions)

• Swap: 1 medium onion → about 1 cup chopped green onions (roughly 1 bunch)
• Best for: Stir-fries, eggs, salads, salsas, tacos, anything finished quickly
• Skip it for: Long braises and caramelizing — there is no bulk here to melt down

Treat a scallion as two ingredients. The white and light green base behaves like a very mild onion and can go into the pan at the start. The dark green tops are a finishing herb — stir them in off the heat or scatter them on top, because a few minutes of cooking turns them slimy and dull.

This is the swap that works best when the dish is fast. In a stir-fry or a plate of scrambled eggs, nobody misses the onion. In a four-hour stew, scallions vanish without a trace.

Onion Powder

• Swap: 1 medium onion → 1 tablespoon onion powder (McCormick's own conversion)
• Best for: Sauces, soups, marinades, dry rubs, dressings, meatballs and burgers
• Skip it for: Any dish where the onion is supposed to be a visible, textural ingredient

Onion powder is concentrated onion flavor with the vegetable removed, and that is both the appeal and the limit. It dissolves invisibly into a sauce and seasons a rub better than fresh onion ever could. But if your recipe calls for three onions to build the body of a soup, a tablespoon of powder gives you the taste of onion in a thin soup — the substance is simply gone. In that case, add the powder and accept a lighter dish, or bulk it back up with celery or another vegetable.

Add it with your other dry spices rather than at the end, and give it a moment in the fat. It is potent, so start at a tablespoon and taste up rather than down.

Dried Minced Onion (Onion Flakes)

• Swap: 1 medium onion → 3 to 4 tablespoons dried minced onion, rehydrated in an equal amount of warm water for 10 minutes
• Best for: Meatloaf, burgers, meatballs, soups, stews, dips
• Skip it for: Caramelizing, and anything where you want distinct pieces of onion

The overlooked middle ground between fresh onion and powder. Because the pieces rehydrate, you get a little of the texture back — enough that dried minced onion works in a meatball where powder would leave you wondering what was missing.

Rehydrate it first unless the dish has plenty of liquid and a long cook, or the flakes will pull moisture out of whatever they are in. In a stew you can add them dry and let the pot do the work.

Fennel Bulb

• Swap: 1 medium onion → 1 cup chopped fennel bulb (about half a medium bulb)
• Best for: Braises, roasts, soups, tomato sauces, fish dishes, and caramelizing
• Skip it for: Dishes where an anise note would be out of place — most Indian and Mexican cooking
• Health notes: Not an allium at all, so it is a genuine option if you are avoiding onion entirely

The most interesting swap on this list. Fennel gives you the one thing most onion substitutes cannot — real bulk that softens and sweetens with cooking. Raw, it is crisp with a clear licorice note. Cooked, that anise character mellows dramatically and what is left is sweet and rounded, closer to onion than you would expect from the raw taste.

Because it is not an allium, fennel is worth knowing about if you are cooking for an onion allergy or intolerance. It also caramelizes wonderfully — slow-cooked fennel goes jammy in much the same way onion does. Just be honest about the flavor: it flatters a tomato sauce, a pork braise, or a fish stew, and it fights a curry.

Celery

• Swap: 1 medium onion → 1 cup chopped celery (about 2 to 3 stalks)
• Best for: Soups, stocks, stews, tuna and chicken salad, stuffing
• Skip it for: Anything relying on onion's sweetness — celery is savory and green, never sweet

Celery covers two of onion's three jobs: it brings bulk and it brings savory background. What it cannot do is sweeten. If you are making a soffritto or a mirepoix, celery is already in the recipe, so the honest move is to increase it and add something else for sweetness — a grated carrot works, and so does a pinch of sugar in a tomato-based dish. If the dish is a soup and the base is looking thin, a little extra depth from the broth side of the pot covers more than people expect.

It shines in cold applications. Diced celery in tuna salad or egg salad does exactly what raw onion was there for: crunch and a savory lift, with none of the harshness.

Chives

• Swap: Raw onion garnish → ¼ to ⅓ cup snipped chives, added off the heat
• Best for: Potatoes, eggs, sour cream dips, soups as a finish, salads
• Skip it for: Anything cooked. Chives are a finishing herb, not a base

Chives are a garnish that happens to taste like mild onion, and they should be treated accordingly. Snip them over the finished dish or fold them in after the pan is off the heat — cook them and you get limp green threads and almost no flavor.

This is not a swap for the onion in your stew. It is the swap for the raw onion sprinkled over the top of it, and for that it is excellent.

Asafoetida (Hing)

• Swap: 1 medium onion → about ¼ teaspoon asafoetida, bloomed in hot oil or ghee for 2 to 5 seconds before the next ingredient goes in
• Best for: Indian dals and curries, lentil dishes, low-FODMAP and allium-free cooking
• Skip it for: Anything needing bulk or texture, and dishes where the flavor would read as out of place

The secret weapon of Jain and Hindu cooking, which has done without onion and garlic for centuries and does not taste deprived. Asafoetida is a dried resin that smells genuinely unpleasant in the jar and transforms in hot fat into something remarkably close to the savory allium background you are missing.

Two rules. Bloom it in fat for a couple of seconds only, then add your next ingredient — it burns almost instantly and turns bitter. And use less than you think: start at ¼ teaspoon and work up, because too much is harsh and unmistakable. Check the label if you are eating gluten-free, since many brands are cut with wheat flour.

Which One for Which Dish

• Raw (salads, salsas, sandwiches, vinaigrettes): Shallots first, then green onions, celery for crunch, chives to finish
• Cooked base (soffritto, curries, soups, stews): Shallots or leeks, with celery and fennel to rebuild bulk, and onion powder or asafoetida for depth
• Caramelizing: Shallots, leeks, or fennel — these are the only three with enough sugar and substance to go jammy. Powder and flakes cannot do this at all
• Quick dishes (stir-fries, eggs): Green onion whites
• No bulk needed (sauces, rubs, dressings): Onion powder

If You Are Avoiding Onion for FODMAPs

This is the reader with the fewest good resources and the most at stake, so it deserves real detail rather than a line in a table.

Onion is high in fructans, and fructans are the F in FODMAP. The crucial fact is a chemical one: fructans are water-soluble but not fat-soluble. Monash University — the institution that developed the low-FODMAP diet — is direct about what that means, and it kills the most common piece of internet advice:

The fructan content in onion and garlic are soluble in water... the strategy of putting a whole onion or garlic clove into a soup and then pulling the pieces out before consuming the soup will not work, as the fructan content will have already leached into the water.

So simmering an onion in your soup and fishing it out later does nothing at all. The fructans are already in the broth. But the same chemistry gives you a genuine workaround, because Monash notes that in an oil-based dish the fructans will not leach out — so in a stir-fry, you can add a large piece of onion, cook it in the oil, and pull it out. That is also exactly why onion-infused oil works: the flavor compounds move into the oil and the fructans stay put, because there is no water for them to dissolve into.

Your practical toolkit, then:

• Onion-infused oil — sizzle onion pieces in olive oil, then remove every piece before cooking. Flavor stays, fructans do not
• Dark green tops of scallions and leeks — the safe part. Stop cutting where the color starts turning lighter green; the white and light green parts are the high-FODMAP portion
• Chives — lab-tested by Monash and a reliable mild onion note
• Asafoetida — a pinch in hot oil, as above

The frustrating irony is that the compound causing the trouble is the same one doing the good, which brings us to what you actually give up.

What You Lose (and Whether It Matters)

Most substitution posts frame the original ingredient as the thing to escape. Not here — the onion is the healthy one, and it is worth knowing what walks out the door with it.

Onion is one of the richest everyday sources of quercetin, a flavonoid tied to antioxidant activity. New Mexico State University's extension service puts the range at 22.40 to 51.82 mg per medium onion, and cites Wageningen research finding that quercetin absorption from onions is roughly twice that from tea and more than three times that from apples — so it is not just present, it is unusually available. A kitchen aside worth knowing: quercetin concentrates in the outer layers, with the outermost scales carrying vastly more than the inner ones, so peeling off three layers to get to the "clean" part throws away most of it.

Onion is also a major dietary source of inulin-type fructans, which are prebiotic — food for your gut bacteria. A 2022 review found inulin-type fructan intake increased Bifidobacterium abundance roughly 1.8 to 3.8-fold, alongside improved laxation and intestinal barrier function.

Here is the honest accounting. Swap to shallots, leeks, or scallions and you have stayed in the allium family — you keep most of this. Swap to fennel or celery and you lose the allium compounds but gain a different plant, which is its own kind of win if you are counting plant diversity rather than counting onions. Swap to onion powder and you are getting flavor, not vegetables. None of this should stop you from making dinner tonight with what you have. It just means that if you are choosing between shallots and powder and both would work, the shallots are doing more for you.

What Not to Use

• Garlic, as a one-for-one swap. The most common mistake. Garlic is a seasoning, not a bulk aromatic — a cup of garlic where a cup of onion went is not a substitution, it is a completely different and much more aggressive dish. Add garlic alongside a real substitute, not instead of one. (If you are out of that too, the fresh garlic guide has the conversions)
• Onion salt, without doing the math. It is mostly salt. Swapping a tablespoon of onion powder for a tablespoon of onion salt can add well over a thousand milligrams of sodium. If you use it, cut the recipe's salt accordingly
• Onion powder in raw dishes. In a salsa or a fresh salad it tastes dusty and slightly bitter with nothing to dissolve into and no heat to bloom it. Use shallots or scallions instead
• Fishing the onion out of a soup for FODMAP reasons. As above — the fructans are already in the liquid. This one is worth repeating because the advice is everywhere and it does not work
• Doubling the celery and calling it done. Celery cannot sweeten. Without carrot, fennel, or a pinch of sugar, the dish reads flat and vegetal in a way that is hard to diagnose later

The Short Version

If you have shallots, use shallots. If you have leeks and the dish gets cooked down, use leeks. If you need onion flavor with no onion at all — for a FODMAP reason, an allergy, or a religious one — the answer is not one ingredient but a technique: infused oil for the flavor, fennel or celery for the bulk, asafoetida for the depth.

The catch with any of this is that a general guide cannot know your recipe. Whether shallots or fennel is right depends on the other twenty things in the pot. That is the gap Eat Well Planner's AI recipe chat fills — it can see your actual recipe and tell you which of these fits that dish, and if you are cooking around an intolerance, Recipe Variations will rewrite the whole thing with the swaps already worked in rather than leaving you to adapt it line by line. And when a swap trades one plant for another, Plant Points quietly counts it as a win rather than a compromise.