Instructions

1. Use equal portions butter and shortening in your recipe. Some American buttercream recipes only use butter, but it has a melting point of 88 to 98 degrees Fahrenheit. Shortening has a melting point of 106 degrees F. Use a good quality, white vegetable shortening.

2. Increase the amount of confectioner’s sugar you use in your recipe. Most recipes use a two-to-one ratio of powdered sugar to fats. For a stiffer frosting that crusts over, you’ll want to increase your powdered sugar by 1 to 2 cups -- or until your frosting is stiff but still spreadable.

3. Add cornstarch to your frosting. Cornstarch absorbs moisture and helps your buttercream crust over once it’s spread on the cake. Add a tablespoon at a time until the frosting is stiffer, but still spreadable.

4. Avoid mixing your frosting at high speeds. High speeds incorporate air bubbles that make your consistency too fluffy and airy to tighten up and crust over. If you can, mix by hand or use a hand mixer on a low speed setting.

5. Mix your frosting recipe the night before you plan on using it and refrigerate it to tighten the fats. Bring the frosting to room temperature before using it so that it easily spreads.

6. Spread the frosting on the cake using a cake spatula. Once you’re done, set the cake in the refrigerator uncovered until the frosting crusts over. If storing in the refrigerator, wrap loosely with plastic wrap to keep excess moisture from resting on top of your frosting.