Ingredients:

  • 1.5 cups all-purpose flour
  • 1 cup granulated sugar
  • 1.5 tsp baking powder
  • 0.25 tsp salt
  • 0.5 cup unsalted butter, room temperature
  • 3 large egg whites
  • 0.25 cup full fat sour cream
  • 0.5 cup whole milk
  • 2 tsp vanilla extract
  • 0.5 tsp almond extract
  • 0.5 cup rainbow jimmies
  • 1 cup unsalted butter, softened
  • 3.5 cups powdered sugar
  • 2.5 tbsp heavy cream
  • 1 tsp vanilla extract
  • 1 pinch salt

Instructions:

  1. Preheat your oven to 350°F and line a 12 cup tin. Note: Preheating for at least 20 minutes ensures the stone or metal is truly at temperature.
  2. Sift the 1.5 cups all purpose flour, 1.5 tsp baking powder, and 0.25 tsp salt into a bowl. Note: Sifting prevents flour pockets in the finished bake.
  3. Beat the 0.5 cup unsalted butter and 1 cup granulated sugar until the mixture looks pale, fluffy, and smells like sweet cream (about 3 minutes).
  4. Add the 3 large egg whites one at a time, followed by the 0.25 cup sour cream and extracts. Note: Don't worry if it looks slightly curdled; the flour will fix the emulsion.
  5. Add half the dry ingredients, then the 0.5 cup whole milk, then the remaining dry. Mix until just combined and the batter looks silky.
  6. Gently stir in the 0.5 cup rainbow jimmies by hand. Stop as soon as they are distributed to avoid streaks.
  7. Divide batter into liners. Bake 18 minutes until the tops spring back and the kitchen smells like a nostalgic bakery.
  8. Move cupcakes to a wire rack. Note: Frosting a warm cupcake will result in a melted, oily mess.
  9. Beat the 1 cup butter and 3.5 cups powdered sugar with cream and vanilla. Beat until it looks like a voluminous, white cloud.
  10. Pipe generous swirls onto each cupcake and top with extra sprinkles before the frosting crusts over.