A grown-up funfetti birthday layer cake made with bourbon whiskey and extra vanilla in both the batter and buttercream frosting then adorned with two kinds of rainbow sprinkles
Preheat oven to 350 degrees. Grease and flour four round, 8-inch cake pans. Whisk together flour, sea salt, baking powder, and sprinkles. Set aside.
In another bowl, beat together butter, sugar, and brown sugar then add in eggs, vanilla, bourbon, and milk.
Add about two cups of the dry mixture to your wet ingredients at a time, mixing well between each addition. Stir until uniform and no dry pockets exist.
Divide cake batter between four pans and bake for about 30 minutes or until a toothpick inserted in the center of each cake comes out clean. Wait a few minutes before removing cakes from pans then cool on a wire rack.
While cakes bake and cool, mix the frosting ingredients. First, beat the butter until it lightens in color (30 seconds to one minute) then add powdered sugar, a cup or so at a time, alternating each addition with bourbon, vanilla or milk. Add sea salt with last addition then beat until all ingredients are incorporated and frosting is uniform. It may be necessary to scrape down the bowl with a rubber spatula periodically. This recipe makes enough frosting for a naked cake look, which is basically filling between each layer and a crumb coat all over.
Frost and assemble cake once fully cooled: Spread about 1/2 cup of frosting on top of your first cake layer, spreading to about 1 1/2 inch from the edge before adding the next layer. Repeat until assembled. Frost the top and side of cake with a crumb coat.
Use the remaining frosting to make a few swirls on the top of the cake as pictured and to spread a one-inch layer around the base of the cake. Cover this layer with nonpareil sprinkles. Add additional sprinkles to top of cake. Chill finished cake if not serving immediately.
Nonpareils (the little round rainbow sprinkles) will bleed their colors into cake batter so I only used them to decorate the finished cake. The jimmies are folded into the batter to create the funfetti effect.
If your frosting becomes to0 soft as you're working with it, chill the cake and frosting for a bit then resume. I recommend chilling the cake once you have finished the crumb coat if you plan to do another full layer of frosting and/or more elaborate decorations.