Birthday Cake

Name: Birthday Cake
Prep time: 2 h
Cook time: 30 min
Total time: 2 h 30 min
Cuisine: American
Ingredients: 1 cup unsalted butter (melted); 1 1/2 cups granulated sugar; 3 large eggs (room temperature); 1 tablespoon vanilla bean paste (substitute vanilla extract ); 1/4 teaspoon almond extract (optional); 1 cup buttermilk (substitute whole milk); 2 1/2 cups cake flour (substitute all purpose flour); 2 teaspoons baking powder; 1/2 teaspoon kosher salt; 1/2 cup rainbow sprinkles; 1/4 cup unsalted butter (melted); 3/4 cup cake flour (substitute all purpose flour); 1/2 cup granulated sugar; 1/4 teaspoon baking powder; 1 teaspoon vanilla extract; 2 tablespoons rainbow sprinkles; 1 cup unsalted butter (room temperature ); 3 cups powdered sugar; 1/4 teaspoon kosher salt; 2 teaspoons vanilla bean paste (substitute vanilla extract ); 2-4 tablespoons milk (as needed for desired consistency); 1/4 cup milk