If you are all out of these two classic leavening agents, you'll need to go old school and use whipped egg whites. You typically need to whip 2-3 egg whites to stiff peaks, then fold them into your batter right at the end before baking. Be sure to weigh the egg whites first to remove the same amount of liquid to ensure the proper texture. You can also use ingredients like buttermilk or sour milk, which can help a batter rise slightly on its own.