Five fixes for flat cookie fails.

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Are your cookies turning out flat, and you dont know why?

Flat cookies are a common kitchen mystery that can leave many home bakers scratching their heads.

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Photo:SDI Productions/Getty Images

Incorrect Butter/Fat Temperature

Most cookie recipes call forroom-temperature butter, and theres a good reason for that!

Although its tempting to microwave butter when you want it to be at room temperature, resist the urge.

This, in turn, could be why your cookies are flatter than you might like.

Over-Mixing the Dough

Over-mixing cookie dough creates extra gluten, yielding a tougher, flatter cookie.

When you integrate the wet and dry ingredients, only mix until the ingredients are combinedno longer than necessary.

Dont worry if there are a few streaks of flour left!

Expired Leavening Agents

Yes,baking powderandbaking sodacan expire!

Expired leavening agents lose their effectiveness, leading to flat cookies.