2 1/4 cups cake flour (9 ounces)
1 cup whole milk, at room temperature
6 large egg whites (3/4 cup), at room temperature
2 teaspoons almond extract
1 teaspoon vanilla extract
1 3/4 cups granulated sugar (12 1/4 ounces)
4 teaspoons baking powder
1 teaspoon table salt
12 tablespoons unsalted butter (1 1/2 sticks), softened but still cool
Red, orange, yellow, green, blue, and purple gel food coloring

For Frosting/Filling:
2 1/2 cups granulated sugar
10 large egg whites
2 pounds (8 sticks) unsalted butter, cut into tablespoons, softened
2 teaspoons pure vanilla extract
1 pound best-quality white chocolate, melted and cooled