Preheat your oven to 350 degrees F and grease 3 9 inch cake pans
In a bowl sift together the flour, baking powder, baking soda, and salt. Set aside
In another bowl with an electric mixer cream the butter and sugar until smooth any creamy, about 5 minutes
Scrape down the sides and add in the 4 large eggs. Beat until mixed completely
Add in the vanilla extract and buttermilk and stir until combined completely
In a another bowl with clean beaters whip the egg whites until stiff peaks form, about 5 minutes, and set aside
To the buttermilk mixture add in the dry ingredients. Mix until just combined. Don’t over mix the batter!
Using a spatula gently fold in the egg whites. Once combined fold in the sprinkles
Divide the batter into the three pans and put into your preheated oven to bake for 25 minutes, or until a cake tester comes out clean
Let them cool completely (I let mine sit overnight!) before frosting
In a large bowl cream the softened butter until smooth, about 5 minutes
Add in the powdered sugar, heavy cream, vanilla, and salt. Mix until completely smooth
Add a cake layer on your stand of choice and cover the top completely with frosting. Continue with all three layers
Frost the sides and top of the cake evenly and then set the cake on a sheet try lined with foil
Use your hands to sprinkle the top and sides with the sprinkles with as many as you’d like! (This step is optional)
That’s it! The most festive, delicious cake ever! Time to celebrate!