The most extraordinary moist Homemade Vanilla Cake Recipe made by preheating oven to 350°F greasing flouring and lining two 9-inch pans whisking 3 cups flour 2 tsp baking powder and 1/2 tsp salt beating 1 cup softened butter medium-high 1 to 2 minutes until creamy adding 2 cups sugar beating 2 minutes light and pale and fluffy adding 3 room temperature eggs and 2 extra yolks one at a time beating thoroughly then 2 tsp vanilla stirring 1/2 cup room temperature sour cream and 1/2 cup room temperature whole milk on low alternating flour in 3 additions with sour cream milk in 2 additions beginning and ending with flour just combined between each not overmixing dividing between pans baking 28 to 32 minutes until toothpick clean and tops spring back cooling 10 minutes then on racks then beating 1 1/2 cups room temperature butter medium-high full 4 minutes until incredibly pale and aerated adding 5 to 6 cups sifted powdered sugar one cup at a time on low adding cream vanilla and salt increasing to medium-high beating 3 more minutes incredibly light and fluffy assembling with generous buttercream between and over layers decorating with sprinkles. A completely perfect moist buttery sour cream extra yolk vanilla whipped buttercream two-layer birthday celebration cake recipe.