If the cookies over-spread, it's often a result of butter that’s a bit too soft. Allow butter to sit out for about 2 hours before using, not overnight. (The amount of time depends on the weather and how cool you keep your kitchen.) To test the butter, poke it with your finger. Your finger should make an indent without sinking or sliding down into the butter. The butter should not be shiny or greasy, cool to the touch, and not warm.