Baked Alaska

Name: Baked Alaska
Ingredients: Cooking spray; 2 pints ice cream ( any 2 flavors), softened in the fridge for 30 minutes; 1 quart ice cream , any flavor, softened in the fridge for 30 minutes; 1 loaf pound cake , store-bought or homemade; 6 large egg whites , room temperature; 1/4 teaspoon cream of tartar; 1/4 teaspoon kosher salt; 1 cup ( 200 g ) granulated sugar; 1/3 cup water