Here we are. It’s the day before Halloween and instead of sharing cute spooky treats or gruesome eats, my mind is only on one thing – this dreamy confection. Can you blame me? This pretty party cake with fluffy white frosting and a rainbow array of brightly colored sprinkles is irresistibly fun. I imagine it could put a smile on almost anyone’s face – even the Grinch (pre-revelation) or Mr. Gru (pre-Edith, Agnes and Margot.)

This cake is a joy to make for anyone who loves baking. Though it isn’t terribly more complex than any other layer cake, it uses a few different techniques which are all part of the signature Milk Bar layer cake method. The cake is baked in a quarter sheet pan and then rounds are cut from that to create the layers. The cake layers are brushed with a soak to add flavor and seal in moisture, and birthday cake crumbles are sandwiched between the layers and sprinkled on top. You might wonder whether it is worth the extra effort. As far as I am concerned, it absolutely is! I’m sure you could achieve a similar result baking in round pans right off the bat, but I like this method best. Though a 6-inch round cake may not seem like much, the slices are so rich that you really only need a small one to be fully satisfied. What a perfect way to say happy birthday! Or, you know, happy Friday/I’m craving cake day. Whatever.

  • Yield 10-12 servings

Ingredients

For the cake crumbles: 

  • ½ cup (100 grams) granulated sugar
  • 1½ tbsp. (25 grams) light brown sugar
  • ¾ cup (90 grams) cake flour
  • ½ tsp. (2 grams) baking powder
  • ½ tsp. (2 grams) kosher salt
  • 2 tbsp. (20 grams) rainbow sprinkles
  • ¼ cup (40 grams) grapeseed oil
  • 1 tbsp. (12 grams) vanilla extract

For the cake: 

  • 4 tbsp. (55 grams) unsalted butter, at room temperature
  • 1/3 cup (60 grams) vegetable shortening
  • 1¼ cups (250 grams) granulated sugar
  • 3 tbsp. (50 grams) light brown sugar
  • 3 large eggs
  • ½ cup (110 grams) buttermilk
  • 1/3 cup (65 grams) grapeseed oil
  • 2 tsp. (8 grams) vanilla extract
  • 2 cups (245 grams) cake flour
  • 1½ tsp. (6 grams) baking powder
  • ¾ tsp. (3 grams) kosher salt
  • 6 tbsp. (75 grams) rainbow sprinkles, divided

For the frosting: 

  • 8 tbsp. (115 grams) unsalted butter, at room temperature
  • ¼ cup (50 grams) vegetable shortening
  • 2 oz. (55 grams) cream cheese
  • 1 tbsp. (25 grams) glucose
  • 1 tbsp. (18 grams) corn syrup
  • 1 tbsp. (12 grams) vanilla extract
  • 1¼ cups (200 grams) confectioners’ sugar
  • ½ tsp. (2 grams) kosher salt
  • Pinch baking powder
  • Pinch citric acid

For the soak: 

  • ¼ cup (55 grams) milk
  • 1 tsp. (4 grams) vanilla extract

Directions

  • 01

    To make the crumbles, heat the oven to 300˚ F. Line a baking sheet with a silicone baking mat or parchment paper. In the bowl of an electric mixer, combine the sugar, flour, baking powder, salt and sprinkles. Mix on low speed until combined. Add in the oil and vanilla and mix until the dry ingredients start to form small clusters. Spread the clusters on the prepared baking sheet. Baking for 20 minutes, breaking them up occasionally. Remove from the oven. The crumbs will dry and harden as they cool. Cool completely before using.

  • 02

    To make the cake, heat the oven to 350˚ F. Butter and flour the edges of a quarter sheet pan. Line the bottom of the pan with parchment paper. In the bowl of an electric mixer, combine the butter, shortening and sugars. Beat on medium-high speed for 2-3 minutes, until fluffy. Scrape down the sides of the bowl, add in the eggs, and mix on medium-high for 2-3 minutes more. Scrape down the sides of the bowl again.

  • 03

    With the mixer on low speed, stream in the buttermilk, oil and vanilla. Increase the speed to medium-high and mix for 4-6 minutes, until the mixture is nearly white and twice the size of the original batter, and completely homogenous (there should be no streaks of fat or liquid.) Scrape down the sides of the bowl. With the mixer on very low speed, add in the cake flour, baking powder, salt and ¼ cup (50 grams) of the sprinkles. Mix for 45-60 seconds, just until the batter comes together. Spread the batter in the prepared quarter sheet pan. Sprinkle the remaining 2 tablespoons (25 grams) of sprinkles evenly over the surface.

  • 04

    Bake for 30-35 minutes, rotating the pan once halfway through baking, until the cake is puffed and the center is no longer jiggly (the cake should bounce back when lightly poked with your finger.) Transfer to a wire cooling rack and let cool completely.

  • 05

    To make the frosting, combine the butter, shortening and cream cheese in the bowl of an electric mixer. Beat on medium-high until smooth and fluffy, about 2-3 minutes. Scrape down the sides of the bowl. With the mixer on low speed, stream in the glucose, corn syrup and vanilla. Increase the speed to medium-high and beat 2-3 minutes, until the mixture is silky smooth and glossy white. Scrape down the sides of the bowl. Add in the confectioners’ sugar, salt, baking powder, and citric acid. Mix on low speed just to incorporate. Increase the speed to medium-high and beat 2-3 minutes. Use immediately or store in an airtight container and refrigerate for up to 1 week.

  • 06

    To assemble the cake, invert the cake from the sheet pan onto a work surface. Use a 6-inch cake ring to cut out 2 circles from the cake (these will be the top two layers.) Wipe off the cake ring and place it in the center of a sheet pan lined with clean parchment or a silpat. Use a strip of acetate to line the inside of the cake ring. Use scraps from the leftover cake to place in the ring and tamp together in a flat, even layer. Whisk together the milk and vanilla for the soak. Use a pastry brush to soak the cake with about half of the liquid mixture.

  • 07

    Spread one-fifth of the frosting in an even layer over the cake. Sprinkle one third of the birthday crumbs evenly over the top of the frosting. Press down gently to anchor in place. Spread a second fifth of the frosting as evenly as possible over the crumbs. Gently tuck a second strip of acetate between the cake ring and the top ¼-inch of the first strip of acetate. Set a cake round on top of the frosting, and repeat the layering process once more (brush with soak, frosting, crumbles, frosting.) Place the remaining cake layer onto the frosting. Cover the top with the remaining fifth of the frosting and garnish with the remaining birthday crumbs.

  • 08

    Transfer the assembled cake to the freezer and freeze for a minimum of 12 hours to set the cake and the filling. At least 3 hours before you are ready to serve, remove the pan from the freezer, pop the cake out of the cake ring, and peel away the acetate layers. Transfer to a cake platter and defrost for at least 3 hours before slicing and serving.

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