Make the Cake Layers

1. Preheat oven to 350˚F. Grease 3 8″ straight edge cake pans. Line with parchment paper and grease.
2. In a medium bowl, sift together flour, baking soda, baking powder, and salt together. Whisk until completely mixed.
3. In a standing mixer or with a hand held mixer and a large bowl, cream butter and sugar until light and fluffy, about 5 minutes.
4. Whisk in eggs, egg whites, vanilla extract, vanilla paste, and oil on a high speed until combined, about 2 minutes, scraping down sides as needed.
5. On a low speed, whisk the flour mixture to the egg mixture until just combined.
6. Still on a low speed, pour in the buttermilk and skim milk, mixing until just combined.
7. Gently fold in sprinkles until just combined.
8. Pour batter evenly into greased layer pans. Bake for 25-30 minutes, until a toothpick comes out clean when inserted into the center of each cake. Set on a wire rack to cool, at least one hour, or frosting will melt.*

Make the Frosting

1. In a standing mixer or with a handheld mixer, whisk butter and cream cheese until light and creamy. Sift in the powdered sugar. Add vanilla extract, vanilla paste, and heavy cream. Whisk until completely smooth. Set aside about 1 cup of the frosting for cake pops (if making).

Assemble the Cake

1. Mix about 2 cups of sprinkles/candy mixture for the center of the cake and 1 to 2 cups of smaller, simpler sprinkles for the outside of the cake in two different bowls. Set aside.
2. When the cake layers are cooled, place the cake layers with the flat side down. Use a 2-inch round cookie cutter to cut out the center of each layer except for the one you will be using for the top of your cake. If making, save the cut out pieces for the cake pops!
3. Place a little bit of the frosting in the shape of your first cake "ring" layer on your cake stand, board, etc. to make sure the cake won't move while assembling. Lay the first cake layer on top of this frosting ring. With an offset spatula, spread the top of the layer with about 1/2 cup of frosting. Repeat for the next four layers. *Make sure to leave a little space between the frosting and the hole or your sprinkles will stick to the frosting and won't "explode" when sliced. Also make sure the layers line up!*
4. Pour the sprinkles reserved for the center of cake down the hole.
5. Add on the final layer (the one without the 2 inch hole), flat side up to make the cake even. Lightly frost the rest of the cake with half of the remaining frosting to create a crumb coat. Place cake in fridge and chill for 10 minutes.
6. Remove cake from the fridge and frost with remaining frosting. Cupping your hands, scoop up some of the sprinkles reserved for outside of the cake. Tilting your hands, slowly move them up the sides and across the top of of the cake so the sprinkles spill out and stick to the frosting (I found it enormously helpful to have a piece of parchment paper underneath my cake stand, it help to stop the sprinkles that didn't stick from bouncing away too much). Garnish the top of the cake with any other decorations as desired (Cake pops, Animal Circus Cookies, Pirouettes, Pocky Chocolate Biscuit Sticks, etc). See below for cake pops instructions!
7. Cover cake tightly and store in the fridge for 4-5 days.

Optional: Make Cake Pops

1. In a medium size bowl, crumble the reserved cake layer pieces with your hands.
2. Stir in reserved frosting 1/4 cup at a time until the filling can be rolled into a ball.
3. Form into balls, add a stick to each one, and place in the freezer until ready to coat in candy meltable topping.
4. Set up a cake pop stand, styrofoam block, or artfully stack two wire racks on top of each other so that once dipped, the cake pops will harden while standing upright.
5. When ready to coat the cake pops, melt the candy melts according to the instructions on the packaging.
6. Dip each frozen cake pop into the melted mixture, swirling around gently to coat. Stand upright to harden. Let cool 10-12 seconds and top with sprinkles as desired.
7. Once hardened, you can store them flat in an airtight container or ziploc bag in the fridge or freezer until ready to use.