Ingredients:

  • 2 cups (250g) All-purpose flour
  • 1 cup (200g) Granulated sugar
  • 1/2 cup (113g) Unsalted butter, softened
  • 2 large Eggs, room temperature
  • 1 cup (240ml) Whole milk, room temperature
  • 2 tsp (10g) Baking powder
  • 1/2 tsp (3g) Salt
  • 1 tbsp (15ml) Pure vanilla extract
  • 1/2 cup (60g) Rainbow jimmies
  • 1 cup (226g) Unsalted butter, softened
  • 3 cups (360g) Powdered sugar, sifted
  • 2 tbsp (30ml) Heavy cream
  • 1 tsp (5ml) Pure vanilla extract
  • 1 pinch (1g) Salt
  • 2 cups (240g) Rainbow nonpareil sprinkles

Instructions:

  1. Preheat oven to 350°F (175°C). Cream the butter and sugar until pale and fluffy. Beat in eggs one at a time, then stir in vanilla.
  2. Alternately add the dry ingredients (flour, baking powder, salt) and milk, mixing until just combined. Gently fold in jimmies.
  3. Spread batter into a greased 9x13 pan and bake for 20-25 minutes until the center springs back when touched. Cool completely on a wire rack.
  4. Using a circular cutter, punch out 16 equal cake rounds.
  5. Whip the buttercream ingredients (butter, powdered sugar, heavy cream, vanilla, and salt) together until the frosting reaches a stiff peak.
  6. Pipe or spread a generous dollop of frosting onto 8 rounds, then top each with a second cake round to create mini sandwiches.
  7. Place the assembled cakes in the fridge for 20 minutes to firm up.
  8. Fill a shallow bowl with nonpareils. Gently press the top and sides of each chilled cake into the sprinkles, rotating them until the cake is completely encased.