If your baking powder has been in your pantry for a while, make sure it’s still active before you begin baking. You don’t want to ruin your recipe because your baking powder is old. Try this before adding to your recipe – stir 1/2 teaspoon of baking powder into 1/4 cup of hot water. If it bubbles, it’ still good to use. If not, time for a trip to the store!