When a recipe is well written, the baking powder acts as reinforcements to a chemical reaction that is happening with or without the baking powder present. When a recipe has too much baking powder in it…the baking powder can force the cookie to puff more than it would on it’s own. This is an AWESOME thing for cakes.
Use a silicone baking mat or parchment paper. Coating your baking sheet with nonstick spray or butter creates an overly greasy foundation, causing the cookies to spread. I always recommend a silicone baking mat because they grip onto the bottom of your cookie dough, preventing the cookies from spreading too much.
If you prefer the texture of the cookies to be light and fluffy, add baking powder and beat the butter and sugar for longer (I’ll explain more in the recipe). The thing is, by beating too much air into the dough or adding baking powder, the cookies will be more prone to spreading.
In addition, baking powder produces a slightly different texture in cookies than baking soda does. While baking soda will create a coarse, chewy cookie texture, baking powder will produce a light, fine cookie texture. To achieve the best cookie results, use a double-acting baking powder as a substitute.
Good rule of thumb: I usually use around 1 teaspoon of baking powder per 1 cup of flour in a recipe.
The following factors all increase spread in cookies: heavily greased pans, high sugar content, high liquid content, high oven temperature. In the one-stage mixing method, all ingredients are placed in the mixing bowl and mixed together.