Step 1 / 9

digital scale, bowl tared, whites separated one at a time into a cup first

egg whites, separated and weighed into a scrupulously grease-free bowl, and whatever number the scale reads is the anchor for everything that follows. Separate each white into a small cup before adding it to the bowl: one broken yolk contaminates the whole batch, because egg-yolk fat inserts itself between protein chains and stops them linking into a foam at all, and there is no rescuing it. Eggs are not a standard size, so 'three egg whites' is a range of roughly 85 to 115 grams — a 30 percent swing in the one ingredient every other quantity is measured against. That is the whole reason this recipe cannot be made from cups and spoons, and why the scale is equipment rather than a suggestion. Wipe the bowl and whisk with vinegar or lemon juice first if there is any doubt about grease; plastic bowls hold fat in their scratches and should not be used