When you fold in egg whites, you incorporate beaten whites into other ingredients without compromising the airiness of the beaten whites. Folding egg whites properly ensures success with dishes like soufflé, mousse, angel food cake, and more. Folding egg whites isn’t the same as stirring, and it takes a gentle touch, so fold with care.
Stir about 1/4 of your whipped egg whites into your yolk mixture or batter.
This step “tempers” the batter, lightening it a little before you add the rest of the egg whites.
Gently pile the remaining whites on top of the mixture.
Move the whites only as much as necessary — otherwise, you deflate them.
Hold the spatula with the flat side of the spatula facing toward you.
Use a large rubber spatula.
Pull the spatula towards you and turn it to bring some of the yolk or batter mixture over the whites
Bring the spatula straight down into the whites, cutting down through the center of the mixture. Hold the bowl with the other hand for stability.
Give the bowl a quarter turn and repeat the plunging-and-scooping process.
Gently fold the whites about 10 to 15 times, until the whites and yolk mixture are combined.