6hr · 20 servings Cake: • 2 3/4 cups all-purpose flour • 2 cups granulated sugar • 2 1/2 teaspoons baking powder • 1/2 teaspoon Kosher or sea salt • 1 cup (2 sticks) unsalted butter, room temperature, cut into 16 pieces • 4 large egg whites, room temperature • 1 tablespoon pure vanilla extract • 1/2 teaspoon pure almond extract • 3/4 cup full-fat sour cream, room temperature • 1/4 cup whole milk, room temperature Syrup: • 1/4 cup granulated sugar • 1/2 cup water • 1 teaspoon pure vanilla extract • 1/4 teaspoon pure almond extract Marzipan: • 12 ounces prepared marzipan (not almond paste) Poured Fondant: • 2/3 cup hot tap water • 1/2 cup light corn syrup • 2 teaspoons pure vanilla extract • 12 ounces white chocolate chips • 2 pounds (7 1/2 cups) confectioners suga