Rather than being chemically leavened by using baking soda or baking powder, or a natural leavening agent like yeast, choux dough is leavened with steam, similar to puff pastry or a croissant. First the dough is baked at a high temperature and then at a low temperature. The initial high temperature is used to create the steam, thus making the dough rise.
After the dough is baked, you can cut each ball in half and fill them with ice cream or whipped cream. Since the dough is leavened with steam, you can also carefully poke a hole in the bottom and using a piping bag and small tip to fill each with sweet or savory filling. One of my favorite ways to prepare these is to add Gruyère and Parmesan cheese to the batter after adding the eggs, then filling each baked dough with a mornay sauce. These are delicate and flavorful appetizers that are elegant for any party.
Emily Jacobs is the Recipe editor at The Daily Meal. Follow her on Twitter @EmilyRecipes.