Although brown butter is incorporated into many desserts, it’s important to note that melting butter changes its structure. Melted butter does not form air pockets when whipped with sugar, which is crucial for leavening. When a recipe calls for creaming plain butter and sugar, brown butter cannot necessarily be used in its place. However, brown butter can generally be substituted for regular butter in icing, mashed potatoes, lemon curd, and many other luscious items.
How to Brown Butter