Here are three ideas for using the leftover egg whites: 1. Freeze them. I like to freeze them in ice cube trays, one egg white per cube. Once frozen, they can be popped out and stored in a freezer bag or other container for up to 1 year. Thaw as needed in the refrigerator, letting them sit out at room temperature for about 30 minutes so that they come to room temperature before using them in baking recipes. 2. Use them to make Italian Meringue Buttercream. Italian Meringue Buttercream is my all time favorite frosting for cakes and cupcakes. It’s silky smooth, incredibly creamy, and absolutely gorgeous to work with. Even better, the recipe happens to require 8 egg whites. It's kismet. 3. Make a meringue topping for this pie instead of using whipped cream. The only difference between a chocolate meringue pie and a chocolate cream pie is whether it has a whipped cream or meringue topping. If you'd prefer to top your chocolate cream pie with meringue, simply follow the instructions for the meringue topping in this Lemon Meringue Pie recipe. The recipe only requires 4 egg whites, so freeze the remaining 4 if you like for your next meringue topped pie.