Cookie recipes are built from fat, flour, and other ingredients. Sweet cookies may include lemon, orange, vanilla, cinnamon, or chocolate, while savory cookies may use mahleb, thyme, black pepper, or red pepper flakes. In both sweet and savory cookies, the type of fat added to the dough is what most affects its texture. Fat gives cookies structure and texture, and these two fats, butter and oil, contribute different qualities. The same recipe can turn out quite differently when made with different fats.
What Does Butter Add to Dough?
Butter can be added to cookie dough in three ways: at room temperature, melted, or cold. When room-temperature butter is beaten with granulated sugar, the result is a soft, melt-in-your-mouth texture; these cookies spread more during baking and stay slightly soft inside. Cold butter creates a crisper texture similar to pie dough, a method often used in cookie recipes. Butter gives cookies a distinct flavor and color. This difference is more noticeable when using high-fat, good-quality butter.
Signs of Butter-Based Dough
When pressed by hand, butter-based dough gathers together and then crumbles easily; this is typical of this dough. Butter-based dough can be stored in the refrigerator for a relatively long time, making it convenient to prepare ahead and chill. Butter's flavor becomes more noticeable after baking, so it is preferred in recipes where flavor is a priority. Chilling the dough in the refrigerator for at least half an hour before baking helps cookies hold their shape in the oven.
What Does Oil Add to Dough?
Oil can be used when butter is unavailable or when a recipe without solid fat is preferred; it is especially common in savory cookies. Dough made with oil does not come together as quickly as butter-based dough and does not crumble when pressed by hand. It is more elastic and can absorb more liquid. Compared with butter, oil has a lighter flavor and can keep cookies fresh longer. Oil is a suitable choice when a firm, crisp cookie is desired; however, oil-based dough keeps for less time in the freezer than butter-based dough.
Can You Use Both?
Butter and oil can be used together in the same dough. For a crumbly texture, use more butter; for a softer texture, add oil to the mixture. The proportions in these combination recipes are usually determined through testing. The combination aims to bring together butter's flavor and the softness provided by oil, and can be tried when a cookie that is both crisp and tender is desired. Using equal parts of each fat for the first attempt offers a balanced starting point.
When Should You Choose Each One?
Choose butter for rich, flavorful cookies with a shorter shelf life, and oil for cookies that should stay fresh longer and have a lighter flavor and firmer texture. Butter can be a good choice for special cookies served to guests, while oil is practical for everyday cookies. If you replace the type of fat specified in a recipe, adjust the dough's liquid content as needed; otherwise, the texture and baking time may change. Baking a small portion of the dough first lets you check the result without risking the rest of the batch.