Cookies may seem like magic, but they're the result of a whole litany of chemical reactions that come together to create a warm, gooey, toasty, comforting treat. In other words, they're delicious science. Here's how the elements of the perfect chocolate chip cookie come together.
Adding moisture to flour helps kick off the production of gluten, which forms the framework that helps all of your ingredients hold together in a cohesive shape. It also adds toasty flavors as it bakes, thanks to the Maillard reaction. The texture of your final product will differ based on your flour's protein content. Bread flour makes a chewier cookie, while cake flour makes — you guessed it — a cakier cookie.
Eggs are powerhouse baking ingredients, and they contain fat, moisture and protein. Protein helps add a pleasing chew. Fat adds tenderness. Egg whites, full of moisture, release steam as they cook and help make cookies fluffier.
Baking soda and baking powder are activated by acids and release bubbles to add lift to baked goods. Baking soda reacts quickly when it comes into contact with acid. Baking powder, which already contains powdered acids, releases gas in stages during the baking process. That means it makes a fluffier, cakier cookie. Many cookie recipes with brown sugar in them, like our perfect chocolate chip cookie, don't require baking powder, as brown sugar is already acidic.
Plainly put, salt helps make flavors pop. Flaky sea salt adds the perfect crunch, and it's nice sprinkled over the top of your cookies. Salt also helps temper bitterness.
Sugar makes things sweet, but it's also key to texture. Brown sugar contains molasses, which is acidic. As such, it reacts with chemical leaveners to lend more lift. Also, because of its density, brown sugar traps moisture. White sugar adds a crisp texture. Many people think that perfection lies in a blending of the two.
Vanilla adds a warm, distinctive cookie flavor. Skip it, and you'll know something's missing, even if you can't quite put your finger on it.
We like a blend of different sweetness levels in our chocolate chip cookies, as well as a variety of shapes. Tossing in a few larger chips gives you the occasional delightful pocket of chocolate, which feels like a treat. The higher the cacao level in your chips, the more bitter they will taste. A blend of bittersweet and milk chocolate seems to strike a perfect balance.
Full of fat, butter is a key component of both the texture and flavor of cookies. Unsalted butter is typically of higher quality. You can use salted butter, but just make sure to adjust the salt content of your recipe. Want a chewy-crisp cookie, like in our ultimate chocolate chip cookie recipe? Melt your butter first.
Mackensy Lunsford is the food and culture storyteller for USA TODAY Network's South region and the editor of Southern Kitchen. Reach her at firstname.lastname@example.org.