Dietary Substitutes - My Kitchen Answers

Adapting a recipe for a dietary requirement is a different problem from running out of an ingredient. You’re not looking for the closest match you happen to have — you need something that works every time, and you need to know honestly where the substitution stops working.

This page covers dairy-free, egg-free and vegan, gluten-free, and vegetarian or pescatarian swaps, with the amounts to use and the limits worth knowing.

Dairy-free

Milk

Substitute unsweetened, unflavoured plant milk 1:1 for dairy milk. The useful trick is matching by fat: soy, cashew or well-shaken canned coconut milk stand in for whole milk, while almond, rice or coconut milk beverage suit recipes calling for skim or low-fat.

Soy milk is the standout where browning matters. Its protein content drives the same browning reaction dairy does, which is why King Arthur’s test kitchen picked it as the best vegan egg wash. Rice and almond milk are the thin, low-protein options that behave least like whole milk.

Buttermilk

1 tablespoon lemon juice or vinegar plus enough plant milk to make 1 cup, left to stand about 5 minutes. This leavens correctly, which is what buttermilk is usually there for. For a full breakdown of substitutes for when you’re just out of buttermilk (not avoiding dairy), see How to Use the Best Buttermilk Substitutes for Baking.

Heavy cream

Be clear which job you need it to do, because the answers are different.

For cooking and baking: the thick top half of a can of full-fat coconut milk substitutes roughly 1:1 in fillings and sauces.
For whipping: chill a can of full-fat coconut milk, skim only the solid top layer — about ¾ cup from a 10oz can — and whip it with a frozen bowl and beaters. America’s Test Kitchen is honest that it won’t be as lofty or as stable as real whipped cream, and it carries a mild coconut flavour. That’s for dairy-free whipping specifically. For heavy cream in a savoury sauce, see Best Heavy Cream Substitute for Pasta and Sauces.

Butter

Vegan butter or margarine: 1:1 in cookies, cakes, pastry and pie crust
Coconut oil or shortening: 1:1, expecting small differences in flavour and texture
Liquid oil: about ⅝ cup per 1 cup of butter, because butter is roughly 16–18% water

Oil can’t be creamed with sugar, so it won’t aerate a butter cake or creamed cookie the way solid fat does. If the recipe starts with “cream the butter and sugar,” a solid fat is the better swap. For cookie-specific ratios, see Butter Substitutes for Cookies.

Egg-free and vegan

Flaxseed or chia “egg”

1 tablespoon ground flaxseed plus 3 tablespoons water per egg, rested 5 to 10 minutes until it thickens. Ground chia uses the same ratio.

Good for cookies, brownies, bars, muffins, quick breads and yeast breads. Not for anything that needs to be light — neither flax nor chia aerates, so delicate cakes fall flat. If eggs aren’t the concern and you’re just out (for baking generally), see Egg Substitutes for Baking.

Aquafaba

The liquid from a can of chickpeas, and the one egg replacer that genuinely whips.

¼ cup (57g) = 1 whole egg
2 tablespoons (28g) = 1 egg white

For whipping, King Arthur’s formula is 2 tablespoons aquafaba plus ⅛ teaspoon cream of tartar per egg white, and it takes 10 to 15 minutes of beating. It works genuinely well for meringue cookies, pavlova, marshmallow spread and Swiss buttercream, and it works in brownies, snacking cakes and enriched breads.

Where it fails: angel food and chiffon cake, which can collapse into a puddle, plus macarons and amaretti.

Commercial egg replacers

Powdered replacers generally work out to 1 tablespoon powder plus 2 tablespoons water per egg, but follow the packet — brands differ. We haven’t found a credible head-to-head test of the major brands, so we’re not going to rank them.

What can’t reliably be made egg-free

Nothing replicates everything an egg does at once — structure, binding, moisture, emulsification and lift. Substitution reliably fails for soufflés and quiches, custard-based pies, sponge and hot milk cakes, chiffon and angel food cakes, and any recipe that asks you to beat eggs to the ribbon stage or fold in stiff whites.

For those, use a recipe developed egg-free from the start rather than converting one that wasn’t. Meringue is the honourable exception — aquafaba really does work there.

Gluten-free

Can I swap gluten-free flour 1:1?

Only if it’s a blend sold as “measure for measure” or “1-to-1”, and only in non-yeasted recipes — brownies, cookies, cakes, muffins, scones. Those blends already contain a binder, so don’t add more.

They are not for yeast breads. King Arthur says so directly about their own blend. And swapping a plain gluten-free flour into a conventional recipe generally disappoints: America’s Test Kitchen found bread that was dense and gummy, biscuits that were sandy, and cupcakes that weren’t fluffy, concluding it needs significant reworking rather than a straight swap.

How much xanthan gum?

Xanthan gum does gluten’s two jobs: it binds for structure and holds moisture. Too little and things crumble; too much and the dough turns gluey. Per cup of gluten-free flour:

What you’re making	Xanthan gum per cup of flour
Cookies	¼ tsp
Cakes and pancakes	½ tsp
Quick breads and muffins	¾ tsp
Breads and pizza crust	1 to 1½ tsp

Again: if your blend is labelled 1-to-1 or measure-for-measure, it already has gum in it. Adding more will make things worse.

Unexpected sources of gluten

Soy sauce is the big one — it’s traditionally brewed with wheat, though tamari made without wheat is fine. Others worth knowing: malt vinegar and anything dressed with it, beer and malt drinks, malt extract and malted milk, brown rice syrup made with barley enzymes, self-basting or pre-seasoned poultry, some processed deli meats, and seitan.

One regional catch: Worcestershire sauce is made with malt vinegar in the UK and Canada, but distilled white vinegar in the US. Same brand, different recipe.

Are oats gluten-free? It’s genuinely nuanced

Pure oats don’t contain gluten — they contain a different protein, avenin. The problem is cross-contact: oats are usually grown, transported and milled alongside wheat, barley and rye.

Only oats specifically labelled “gluten free” are tested to the required threshold. “Pure oats,” “100% oats” and “organic” do not mean the same thing and don’t provide that assurance.

A minority of people with coeliac disease also react to avenin itself. If you have coeliac disease and symptoms persist despite eating only labelled gluten-free oats, that’s worth raising with your doctor or dietitian rather than working it out alone.

Vegetarian and pescatarian

Fish sauce

America’s Test Kitchen’s tested version works as a 1:1 substitute: simmer 3 cups water, ¼ oz dried sliced shiitake mushrooms, 3 tablespoons salt and 2 tablespoons soy sauce until reduced by half, then strain. Keeps refrigerated about three weeks. The mushrooms and soy together reproduce the savoury depth. Note it contains soy, and wheat unless you use tamari.

Worcestershire sauce

Standard Worcestershire genuinely contains anchovies, so it isn’t vegetarian. The reliable route is a commercial vegan Worcestershire, or Henderson’s Relish, which is a similar sauce made without fish.

There are plenty of homemade substitute recipes floating around, but we couldn’t find one from a source that had actually tested it, so we’re not publishing a formula.

Gelatin

Agar agar, at about ¾ teaspoon of agar flakes per 1 teaspoon of gelatin, per cup of liquid. Soak it 10 minutes, then boil 10 minutes to dissolve.

Agar behaves differently from gelatin and isn’t a perfect one-for-one replacement in every recipe. It generally produces a firmer, more brittle set, while gelatin gives a softer, more elastic texture. Agar can work in both fruit- and dairy-based mixtures, but recipes such as panna cotta and mousse are usually better made from a recipe specifically developed for agar rather than simply swapping it for gelatin.

Is parmesan vegetarian?

No. Genuine Parmigiano Reggiano is made with calf rennet, and because the name is legally protected, authentic parmesan can never be vegetarian. Pecorino Romano and Gorgonzola are usually not vegetarian either.

Generic “parmesan-style” hard cheeses often use microbial rennet and are fine. Check the label for “microbial rennet” rather than “animal enzymes.”

If you’re cooking for an allergy

Two things worth saying plainly, because they’re often misunderstood.

“May contain” labelling is voluntary and unregulated. The wording doesn’t indicate different levels of risk — “may contain,” “processed in a facility with” and similar phrases aren’t standardised. Food Allergy Research & Education recommends avoiding products carrying precautionary labelling for your allergen, and contacting manufacturers directly when it matters.

Substitutions can introduce new allergens. Aquafaba is a legume. Soy milk and the fish sauce substitute above contain soy. Flax and chia are seeds. Nut milks are tree nuts, and coconut is labelled a tree nut allergen in the US. Swapping one thing out often swaps something else in.

This page is general cooking information, not medical or dietary advice. If you’re managing coeliac disease or a diagnosed food allergy, your clinician or dietitian’s guidance comes first.