Preheat the oven to 350˚F (180˚C). Grease 2 8-inch (20 cm) round cake pans with nonstick spray.
In a large bowl, combine the melted ice cream, cake mix, and egg whites. Whisk until smooth.
Divide the cake batter evenly between the prepared pans. Bake according to the package instructions, about 30 minutes, or until a toothpick inserted in the center of the cakes comes out clean. Let cool completely, about 30 minutes.
Place 1 cake on a cake stand or platter. Spread an even layer of frosting over the cake. Sprinkle ⅓ cup (65 G) sprinkles over the frosting. Top with the other cake layer. Spread a thin layer of frosting over the top and sides of the cake.
Chill the cake in the refrigerator for 15 minutes.
Use the remaining frosting to coat the top and sides of the cake. Cover the top of the cake with the remaining ⅓ cup sprinkles.