It’s happened to everyone. Your pans were prepared and your expectations were high, but for some reason, your cookies came out flat. What happened?
There are a few possible explanations for flat cookies. Before you start over, run through this list. Remember: don’t be too hard on yourself! There’s no use crying over a flat cookie.
Your butter or dough wasn’t cold enough
Butter keeps cookies fluffy in two ways. First, creaming cold butter with sugar creates tiny, uniform air pockets that will remain in the dough it bakes up. Second, cold butter naturally takes a longer time to melt in the oven. When butter melts, the water content evaporates into the dough, giving it body and lightness. Melted butter doesn’t have the opportunity to do that since its water content has evaporated before it was even mixed into the dough. If a recipe does call for melted butter, be sure to refrigerate the dough before baking it to elongate the spreading process. To avoid this problem, don’t leave your dough sitting out on the counter for too long before baking.
Your leavening agent is expired
Let’s admit it: going through a whole box of baking soda or powder can take YEARS, and with most dry ingredients, it can be hard to visibly tell if they’re expired. Things like grains and even flour can last on the shelf for longer than we care to admit, but items with active ingredients expire more quickly, with more detriment. If you followed all the cookie recipe directions to a T and still ended up with flat cookies, check to see if your leavening agent. If it’s expired, try replacing it.
The recipe doesn’t call for enough (or any) brown sugar
Having the right balance of white to brown sugar is key for a cookie’s flavor and texture. Brown sugar takes longer to dissolve, so it creates nice pockets of air in the dough as it melts, similar to cold butter. While white sugar’s lightness is great for beating into (read: fluffing up) cold butter, it also melts and caramelizes quickly, which creates a thin, crispy exterior.
You’re not using enough flour
Without sufficient flour, there is nothing to absorb or hold onto all the fat and liquid from your eggs and butter, causing the dough to spread as soon as it hits the oven. Think back: were you counting your cups carefully? Sometimes it’s easy to miss a scoop.
You’re baking at a higher altitude
At a higher altitude, the air pressure is lower, which means liquids evaporate faster (and leavening happens quicker), and goods take longer to bake. Following low-altitude directions, a cookie would over expand and dry out before it’s cooked through, so try increasing the oven temperature by 20°F and decreasing the baking time.
Can you still eat a flat cookie?
You’re welcome to try! Depending on what went wrong, the cookie may be slightly oily or have a tough texture.