How To Substitute Baking Powder With An Ingredient That's Already In Your Fridge

When you're cooking with baking powder, the first and most important thing to be aware of is that it's a completely different ingredient from baking soda. While some cookie recipes do call for baking soda, those recipes have been carefully calculated for that specific ingredient and no, you cannot simply swap baking soda for baking powder. If you run out of the latter at an inopportune time, what you can do is make a kind of DIY baking powder by mixing two parts cream of tartar with one part baking soda. Cream of tartar isn't a must-buy for many home bakers, though (when's the last time you used it?), but in its absence, egg whites can also serve as a decent baking soda substitute.

Yes, egg whites, strange as it sounds. Egg whites, when beaten, add leavening to a recipe, which is the same purpose that baking powder is meant to serve. If your recipe calls for eggs, just add the yolks, then beat the whites and fold them in later. Two whites have the equivalent leavening power to about a teaspoon of baking powder, so if your recipe needs more baking powder or only uses a single egg, you may need to add another white or two. You should also fold the eggs in carefully so they don't deflate since that would defeat the purpose. However, egg whites probably shouldn't be swapped for baking powder in a fussy recipe that won't stand much tweaking.

If you're out of eggs, there are a few more items in the fridge that might be able to take the place of baking powder. One of these is club soda or seltzer, either plain or, depending on the recipe, flavored. The recipe would need to include liquid, however, so you could swap it out for the soda. The carbonation will provide a little of the missing fizz from the baking powder but not a lot, so this trick works better for flatter items like pancakes or waffles than cakes where you really need some rise.

If you have baking soda on hand, there are a few more things in the fridge that might combine with it to create that acid and base alchemy similar to baking powder. Check your dairy compartment for yogurt, buttermilk, or milk that's gone sour but not yet turned nasty and rotten. For each one of these, ½ cup plus ¼ teaspoon baking soda will replace a teaspoon of baking powder, although you'll need to reduce the liquid in the recipe by ½ cup as well. If you'd like to stay dairy-free or avoid tweaking the recipe measurements, you can also use ½ teaspoon of lemon juice combined with ¼ teaspoon baking soda.