As I start this, I’m hoping that three parts will be enough. There is, after all, more to baking than just fat. But fat is such a critical ingredient that I feel like I need to take the time to explain it. Butter is by far my favorite fat to use in baking. It’s a natural product, it melts in your mouth. It is rich, and it tastes good. Plus, it is a very versatile ingredient. You can use it at so many different temperatures–from cutting in cold butter to make tender biscuits to rubbing in room temperature butter to make a tender cookie to melting some butter into a ganache for added richness to brushing melted butter onto bread before baking for a soft rich crust. See how long that sentence is? That’s at least how useful butter is in the bakeshop!
Frozen butter is hard and splinters when you cut it. Refrigerated butter is firm. Cool butter (65-70 degrees) is plastic, malleable and extensible. Warmer room temp butter (75-85 degrees) is very soft but still emulsified, and above 95 degrees, butter melts. As soon as it hits 212 degrees, it sizzles and bubbles–that’s the water evaporating from the pan. When the butter stops sizzling, that’s when you know all the water is gone. Separate the milk solids at this point, and you’ve got clarified butter, or ghee, the Indian word for it.
Want to go farther? Melt the butter and let the water boil out. The next time it starts sizzling, it’s because the milk solids are frying in the butterfat. Leave it alone, and watch the butter carefully, removing it from the heat when the solids are toasty and brown and straining out the solids, and you’ll have buerre noisette, or nutty and wonderful brown butter.
Use chilled (or even frozen) butter to make a flaky pie crust. Use cool butter to cream together with sugar for cookies and cakes. Use very soft butter to brush into pans or to mix with cinnamon and sugar for cinnamon rolls. Use melted butter to brush onto bread–before or after baking. Use clarified butter or buerre noisette in genoise and madeleines. Buerre noisette is one of the main ingredients in the buttery-rich financier. Oh, but you must make these. They are incredibly rich (hence the name), but my are they tasty!
Please take a look at The Creaming Method for a discussion of creaming for cookies versus creaming for cakes. It is riveting reading and good information.