Combine the egg whites, sugar, water and cream of tartar in the top of a double boiler. Mix thoroughly.
2 large egg whites, 1½ cups granulated sugar, ⅓ cup cold water, ¼ teaspoon cream of tartar
Simmer 2" of water in the bottom of a double boiler of medium heat. Place the top double boiler over the boiling water and beat constantly using an electric mixer on high speed until mixture holds a stiff peak. This will take at least 7 minutes, but most likely closer to 10 minutes.
Remove from the heat. Add vanilla and beat until thick enough to spread.
Makes 5-6 cups of frosting. Perfect for cakes or cupcakes.
Notes
Quick tip: If you’re unsure, keep beating. Most issues with 7 minute frosting come down to not enough time on the mixer.The calories shown are based on the recipe frosting a cake that serves 15, with 1 serving being the frosting for one slice of cake (about ⅓ cup). Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**