How long can you leave cake mixture with baking powder in it before baking it?

Cake mixture with baking powder should ideally be baked within 30 minutes to an hour after mixing. Baking powder starts to activate when it comes into contact with liquid, and its leavening effect diminishes over time. If left for too long, the cake may not rise properly and could result in a dense texture. For best results, it's recommended to bake the mixture promptly.