Momofuku's Birthday Layer Cake

To assemble this cake you will need the following:  (Don't roll your eyes and say this is too much work, it's all very simple)
1 recipe birthday cake
1 recipe birthday cake soak
1 recipe birthday cake frosting
1 recipe birthday cake crumbs
Let's start with the crumbs:

Birthday Cake Crumbs
1/2 cup sugar
1 1/2 tablespoons brown sugar, lightly packed
3/4 cup cake flour
1/2 teaspoon baking powder
1/2 teaspoon kosher salt ( I found the crumbs a little salty, so I cut it back to 1/4 tsp...you decide)
2 tablespoon rainbow sprinkles
1/4 cup grapeseed oil
1 tablespoon CLEAR vanilla extract

Heat the oven to 300 degrees.  In a large bowl, combine the sugars, flour, baking powder, salt and sprinkles.  Mix until they are all combined.  Add the oil and vanilla and stir to distribute.  The wet ingredients are acting as a glue to help the dry ingredients form small clusters, continue stirring until that happens.  Spread the clusters on parchment lined baking sheet.  Bake 20 minutes , breaking them up occasionally.  The crumbs should still be slightly moist to the touch; they will dry and harden as they cool.  Let the crumbs cool completely before using.

Now for the cake...
Birthday Cake
4 tablespoons butter, at room temperature
1/3 cup vegetable shortening
1 1/4 cups sugar
3 tablespoons brown sugar, tightly packed
3 eggs
1/2 cup buttermilk
1/3 cup grapeseed oil
2 teaspoons CLEAR vanilla extract
2 cups cake flour
1 1/2 teaspoons baking powder
3/4 teaspoons kosher salt
1/4 cup rainbow sprinkles
Non stick cooking spray
2 tablespoons rainbow sprinkles
Heat the oven to 350 degrees.  Combine the butter, shortening and sugars in the bowl of an electric mixer fitted with the paddle attachment and cream together on medium-high for 2-3 minutes.  Scrape down the sides of the bowl, add the eggs, and mix on medium-high for 2-3 minutes.  Scrape down the sides of the bowl once more.  On low speed, stream in the buttermilk, oil and vanilla.  Increase the speed to medium-high and paddle for 4-6 minutes, until the mixture is practically white in color and twice the size of the original fluffly butter and sugar mixture and completely homogenous.  Don't rush this process.  You're basically forcing too much liquid into an already fatty mixture that doesn't want to make room for the liquid.  There should be no streaks of fat or liquid.  Stop the mixer and scrape down the sides of the bowl.  On a very low speed, add the cake flour, baking powder, salt and the 1/4 cup rainbow sprinkles.  Mix for 45-60 seconds, just until the batter comes together.  Scrape down the sides again.  Spray a 1/4 sheet pan and line it with parchment.  Using a spatula, spread the cake batter in an even layer in the pan.  Sprinkle the remaining 2 tablespoons sprinkles evenly over the batter.  Bake the cake for 30-35 minutes.  The cake will rise and puff, doubling in size, but will remain slightly buttery and dense.  The cake is done when it bounces back slightly when touched and the center is no longer jiggly.  Cool the cake on a wire rack.

Were 1/2 way home...stick with me
Birthday Cake Soak

1/4cup milk
1 teaspoon CLEAR vanilla extract
Whisk together in a small bowl.  ( Now that was easy, huh?)

Birthday Cake Frosting
1 stick butter, room temperature
1/4 cup vegetable shortening
2 ounces cream cheese
1 tablespoon glucose ( substitute 2 teaspoons corn syrup in a pinch)
1 tablespoon corn syrup
1 tablespoon CLEAR vanilla extract
1 1/4 cups confectioners'sugar
1/2 teaspoon kosher salt
pinch of baking powder
pinch of citric acid

Combine the butter, shortening and cream cheese in the bowl of an electric mixer.  Cream together on medium-high speed for 2-3 minutes, until mixture is smooth and fluffy.  Scrape down the sides of the bowl.  With the mixer on its lowest speed, stream in the glucose, corn syrup and vanilla.  Crank the mixer up to medium-high and beat for 2-3 minutes, until the mixture is silky smooth and glossy white.  Scrape down the bowls.  Add the confectioners' sugar, salt, baking powder and citric acid and mix on low speed just to incorporate them into the batter.  Crank the speed back up to medium-high and beat for 2-3 minutes, until you have a brilliant stark white, beautifully smooth frosting.

Now we assemble....finally!

Put a piece of parchment on the counter.  Invert the cooled cake onto it and peel off the parchment from the bottom of the cake.  Use a 6" cake ring to stamp out 2 circles from the cake.  These are the top 2 cake layers.  The remaining cake "scrap" will come together to make the bottom layer of the cake.

Place the cake ring in the center of a sheet pan, lined with parchment.  Put the cake scraps in the ring and using the back of your hand, tamp the scraps together into a flat even layer.  Dunk a pastry brush in the birthday cake soak and give the layer of cake a good, healthy bath of half of the soak.  Use the back of the spoon to spread 1/5 of the frosting in an even layer over the cake.  Sprinkle 1/3  of the birthday cake crumbs evenly over the frosting and press down with your hand.  Use the back of the spoon to spread another 1/5 of the frosting.    Repeat for the 2nd layer of cake.  Finally, place the 3rd layer of cake onto the frosting.  Cover the top with remaining frosting and garnish with remaining birthday cake crumbs.  Transfer the sheet pan to the freezer and freeze for a minimum of 12 hours to set the cake and filling.   Remove from freezer at least 3 hours before you are ready to serve.  Run a knife between the cake and the cake ring and release the ring.  Place cake on serving pedestal.  Slice into wedges and serve.  Refrigerate uneaten cake (if there is any.....)