“You can cook a piece of chicken, but it will still be just a piece of chicken. I prefer the alchemy of baking.”
“Alchemy?” I asked. “Isn’t that the practice of transforming, uh, stuff, into…”
“Gold,” he said.
That's a reference by food writer, Ari LeVaux to "Food Guy" Greg Patent's concept of "the alchemy of baking," which unites the four ancient Greek elements of earth, air, fire and water in the process of baking.
Here it is, in broad strokes:
Earth is the source of wheat, the dominant grain that led to baking. Utensils are made of minerals, or earth. Fire's heat is essential to baking, and water is essential to creating batters and doughs.
We introduce air to dough and batter by beating it in, or by relying on yeast or chemical agents like baking soda or powder.
Foam cakes depend solely on the air beaten into them to rise. Pastries made of laminated doughs, like puff pastry, enclose butter within a dough, which gets rolled and folded repeatedly. The water in both the dough and the butter turns to steam in the oven, causing the layers of dough to separate and rise.
Soufflés depend on air whipped into the egg whites and folded into the soufflé mixture to rise, while the air beaten into the eggs of cream puff dough causes it to rise. Meringues rise because of the air in egg whites. Yeast, the living leavener, makes bread rise; for quick breads, muffins, scones, and many cakes, so do chemical leavening agents.
(Greg points out that pound cakes are a special class of cake which don't benefit from added baking powder or soda. Traditionally, they're made of butter, sugar, eggs and flour, carefully creamed together to create air pockets that make the dough rise as it bakes.)