Ingredient in meringue cookies

EGGWHITE

["This fluffy cookie component comes from separating an egg and using only the clear part."]

Meringue cookies are made primarily from whipped egg whites and sugar, so the answer "EGGWHITE" directly refers to this key ingredient. The clue is straightforward with no wordplay or hidden meanings—it simply asks for a component of meringue. If you know how meringues are made, this one is easy to solve.