Baking – Is it possible to make cookies without creaming the butter

Creaming puts the air bubbles into the mixture. The baking powder only helps enlarge the bubbles, not make them. In cookies the creaming plays another essential role, which is to help dissolve the sugar. To cream the butter keep it cool and do it for a few minutes (at 65°F, harder in the summer).

It has recently been discovered that cookie dough is different from cake batters. Sugar is part of the structure of the cookie and not just a sweetener, tenderizer, and browning agent. It forms the base upon which the fats and the starch granules of the flour are embedded. The sugar needs to dissolve for the matrix to form.

If you beat the whole thing, it will be harder to get bubbles in and you may end up overworking the dough. The cookies will end up flat and tough.

Your recipe is suspect. Melted butter is the same in chemical composition as softened butter. The two react a bit differently in recipes due to the way that they interact with the other ingredients to impart textures: in short, the creamed butter will hold microscopic bubbles that the fully melted butter will not. Adding egg yolks will help the melted butter incorporate, and probably lead to more cakey cookies (compensating for the flatness you get from melted butter), but the effect is hard to isolate.

As for brown butter, what happens is that as moisture evaporates from the butter, the boiling point increases (similar to what happens when making caramel or candy). As the boiling point of the butterfat increases, the temperature of the butter solids (which consist of lactose and milk proteins) begin to caramelize (the sugars) and undergo a maillard reaction (the protein). Both of these reactions will impart unique flavors to the butter, yielding the distinctive brown butter taste.

As the butter heats, the integrity of the fat is damaged. This occurs to all fats, which is why you can only use a batch of fat for deep frying a few times before it needs to be discarded.