Delicious brownies with nuts on white background
For A Light And Fluffy Brownie, Baking Powder Is A Key Ingredient
For fluffy brownies that are light and cakey rather than fudgy, use baking powder, a leavening agent that is responsible for lifting the batter to create a lighter consistency.
While baking powder is guaranteed to make brownies fluffy, it does need to be fresh. It doesn't necessarily go bad, but it does lose effectiveness if past its expiration date.
To further ensure fluffy brownies, use butter instead of oil since butter also helps the batter rise, and use cocoa powder instead of melted chocolate.
Be sure not to overmix your batter, either. For fluffy brownies, overbeating your batter may end up making them tough in consistency, which is far from ideal.