Ingredient Substitutions: What to Use When You're Out

It always happens at the worst moment. The oven's hot, the onions are already sweating, and you reach for the buttermilk that isn't there. Here's what to use instead, in the amounts that actually work.

The one rule worth knowing

Before swapping anything, ask what the ingredient is doing. Most substitution failures come from replacing an ingredient by name rather than by job.

Buttermilk in a pancake recipe isn't there for flavour — it's an acid, reacting with baking soda to make bubbles. Replace it with plain milk and your pancakes go flat, because you removed the acid without meaning to. An egg in a brownie is binding and enriching; an egg in a sponge is structural. Same ingredient, completely different jobs, and completely different swaps.

Dairy substitutions

You need	Use instead	What changes
1 cup buttermilk	1 tbsp lemon juice or white vinegar + milk to fill 1 cup. Stir, rest 5–10 min.	Thinner and less tangy than cultured buttermilk, but provides the acidity baking soda needs.
1 cup heavy cream (for cooking)	¾ cup whole milk + ¼ cup melted butter	Fine in sauces, soups and bakes. Will not whip.
1 cup sour cream	1 cup full-fat plain Greek yogurt	Nearly identical. Slightly tangier; stir into hot dishes off the heat so it doesn't split.
1 cup whole milk	½ cup evaporated milk + ½ cup water, or 1 cup oat milk	Oat milk browns a little faster in baking. Unsweetened only, unless you want it sweeter.
1 cup butter (in baking)	¾ cup neutral oil	Butter is about 80% fat, so you need less oil. Cakes stay moister; cookies spread more and won't crisp the same way.
1 cup crème fraîche	1 cup sour cream, or ¾ cup sour cream + ¼ cup heavy cream	Less rich, slightly more likely to split at high heat.

Egg substitutions — pick by job

This is the swap people get wrong most often, because "egg replacer" isn't one thing. Work out which job the egg is doing, then choose accordingly. Quantities below replace one egg.

The egg's job	Use instead	Best in
Binding	1 tbsp ground flaxseed + 3 tbsp water, rested 5 min until gloopy	Cookies, muffins, veggie burgers, meatballs
Moisture	¼ cup unsweetened applesauce, or ½ a mashed ripe banana	Quick breads, brownies, muffins. Banana carries flavour — use where you want it.
Richness	¼ cup plain yogurt or silken tofu, blended smooth	Dense cakes, custard-style bakes
Lift / structure	No reliable swap	Sponges, meringues, soufflés, angel food cake — the structure is whipped egg protein

Baking staples

You need	Use instead	What changes
1 cup self-rising flour	1 cup all-purpose flour + 1½ tsp baking powder + ¼ tsp salt	Nothing meaningful. Whisk thoroughly so the leavening is evenly distributed.
1 tsp baking powder	¼ tsp baking soda + ½ tsp cream of tartar	Works well. Mix and bake promptly — it starts reacting on contact with liquid.
1 tsp baking soda	≈3 tsp baking powder (imperfect)	Baking powder is far weaker. Can taste salty or metallic. Avoid if you can.
1 cup brown sugar	1 cup granulated sugar + 1 tbsp molasses	Genuinely indistinguishable. Two tbsp for dark brown sugar.
1 tbsp cornstarch (thickening)	2 tbsp all-purpose flour	Cloudier finish and a slightly floury taste unless cooked out properly.
1 cup granulated sugar	1 cup honey, minus ¼ cup other liquid, oven 25°F lower	Browns much faster and stays moist. Not a straight swap in delicate bakes.

Aromatics, pantry and finishing

You need	Use instead	What changes
1 tbsp fresh herbs	1 tsp dried herbs	Dried is roughly three times stronger. Add early to rehydrate; add fresh late.
1 garlic clove	⅛ tsp garlic powder	Rounder, less sharp. Fine in a braise, noticeable in a dressing.
1 tbsp tomato paste	3 tbsp tomato sauce, reduced in the pan	Extra liquid, so cook it down before adding the rest.
½ cup wine (deglazing)	½ cup stock + 1 tsp vinegar or lemon juice	The acid matters more than the alcohol. Don't skip it entirely.
1 cup stock	1 cup water + aromatics you already have, simmered briefly	Better than plain water. A parmesan rind, onion skin or bay leaf does a lot.
1 lemon's juice	1 tbsp white wine vinegar per 2 tbsp juice	Sharper, no citrus perfume. Fine for balance, poor where lemon is the point.

Four things you shouldn't substitute

• Yeast. There's no pantry swap for it. Baking powder makes a quick bread, not bread — the texture comes from fermentation, and nothing else does that.
• Gelatin in anything that must set. Agar sets firmer and at a different temperature; it isn't a one-for-one exchange, and panna cotta will tell on you.
• Chocolate, in something where chocolate is the dish. Cocoa powder plus fat works in a batter; it doesn't work in a ganache or a mousse.
• Salt, by volume, across types. A teaspoon of table salt is far saltier than a teaspoon of flaky kosher salt. Swap by weight, or taste as you go.

Let the app work it out mid-recipe

Reading a chart with flour on your hands isn't ideal. RecipeScan has substitutions built into the recipe itself: tap any ingredient you don't have and it suggests what to use instead, scaled to the amount that recipe actually calls for, with a note on how the swap changes the result.

It knows what's in your kitchen, too. Scan your pantry once and RecipeScan can prioritise substitutions you can actually make right now — suggesting the yogurt that's in your fridge rather than the crème fraîche that isn't. If a recipe needs several things you're out of, it'll say so plainly instead of walking you into a dish you can't finish.

Frequently Asked Questions

What can I use instead of buttermilk?

For 1 cup, put 1 tablespoon of lemon juice or white vinegar in a measuring cup and top up to 1 cup with milk. Stir and rest 5–10 minutes until it thickens slightly. It won't taste like cultured buttermilk, but it delivers the acidity that reacts with baking soda — which is the job buttermilk is usually doing.

What is a good substitute for heavy cream?

For cooking, replace 1 cup with ¾ cup whole milk plus ¼ cup melted butter. That works in sauces, soups and baked dishes. It will not whip — whipping depends on the fat structure of real cream, so for whipped cream there's no good dairy substitute.

How do I replace an egg in baking?

Decide what the egg is doing first. For binding, use 1 tablespoon ground flaxseed with 3 tablespoons water, rested 5 minutes. For moisture, ¼ cup unsweetened applesauce. For richness, ¼ cup plain yogurt. If the egg provides lift — a sponge, a meringue — substitution rarely works, because that structure is whipped egg protein.

Can I use baking powder instead of baking soda?

Not one for one. You'd need roughly 3 teaspoons of baking powder per 1 teaspoon of baking soda, and it can taste salty or metallic. The reverse is easier: 1 teaspoon of baking powder equals ¼ teaspoon baking soda plus ½ teaspoon cream of tartar.

How much dried herb equals fresh?

Use one third as much: 1 teaspoon dried replaces 1 tablespoon fresh. Add dried herbs early so they rehydrate, and fresh herbs at the end so they keep their aroma.

Does substituting change the cooking time?

Sometimes. Honey and other liquid sweeteners brown faster, so drop the oven about 25°F and start checking early. Oil-for-butter bakes tend to stay moist and can need a couple more minutes. Anything that adds liquid — tomato sauce for paste, for instance — needs that liquid cooked off before you continue.

Want more from what's already in your kitchen? Read what to cook with the ingredients you have, or how Pantry Scan turns a photo of your fridge into a grocery list.