In a medium mixing bowl, sift dry ingredients - flour, baking powder, and salt and whisk to combine. Set aside.
2 cups cake flour, 2 teaspoons baking powder, ½ teaspoon salt
In a large mixing bowl or stand mixer with the whisk attachment, add butter and sugar. Beat on medium low speed and cream until light and fluffy (approximately 3 minutes).
1 cup unsalted butter, 1½ cups white granulated sugar
On low speed, beat in yolks one at a time. Add vanilla and stir until just combined.
8 large egg yolks, 2 teaspoons vanilla extract
Gradually blend flour mixture on low speed, alternating with milk until just combined. Pour mixture into prepared bundt pan evenly.
¾ cup milk
Bake 40 minutes or until a toothpick inserted into the center comes out clean. Place on a wire cooling rack and allow to cool 10 minutes. Gently flip cake onto the wire rack and allow to cool completely. Trim excess from rise off using a knife. Transfer to a cake stand or platter to serve.
To Ice
Transfer icing to a large glass measuring cup. Microwave 40 seconds to melt icing. Stir.
1 cup buttercream icing
Place the cake stand or platter in a sink or on parchment paper to catch runoff. Pour icing over cake in one continuous circle to ensure it spreads evenly and top with sprinkles.
2 tablespoons sprinkles
Notes
Cake Flour Substitute
To make 2 cups cake flour, combine 1¾ cups all-purpose flour with ¼ cup cornstarch.