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Confetti Sheet Cake - A Bright, Happy Cake for Any Celebration

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Prep Time 20 minutes
Cook Time 30 minutes
Total Time 50 minutes
Servings: 12 servings
Ingredients Method

Ingredients
  

  • 2 1/2 cups (315g) all-purpose flour
  • 1 1/2 cups (300g) granulated sugar
  • 2 1/2 teaspoons baking powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon fine salt
  • 1/2 cup (113g) unsalted butter, melted and cooled slightly
  • 1/3 cup (70g) neutral oil (canola or vegetable)
  • 3 large eggs, room temperature
  • 1 cup (240ml) buttermilk, room temperature
  • 1/2 cup (120ml) whole milk, room temperature
  • 2 teaspoons pure vanilla extract
  • 1/2 teaspoon almond extract (optional but recommended)
  • 2/3 cup rainbow “jimmies” sprinkles (plus extra for topping)
  • 1 cup (226g) unsalted butter, softened
  • 3 1/2 cups (420g) powdered sugar, sifted
  • 1/4 cup (60ml) heavy cream or whole milk
  • 2 teaspoons pure vanilla extract
  • Pinch of fine salt

Method
 

  1. Prep the pan and oven: Heat the oven to 350°F (175°C). Grease a 9x13-inch metal baking pan and line the bottom with parchment for easy removal.
  2. Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, baking soda, and salt until evenly combined.
  3. Combine wet ingredients: In a separate bowl, whisk melted butter, oil, eggs, buttermilk, milk, vanilla, and almond extract until smooth.
  4. Make the batter: Pour the wet mixture into the dry ingredients. Whisk gently until just combined with no dry streaks. Do not overmix.
  5. Fold in sprinkles: Using a spatula, fold in the rainbow jimmies. Mix lightly to prevent color bleeding.
  6. Bake: Spread the batter evenly in the prepared pan. Bake 25–32 minutes, or until the top springs back and a toothpick comes out clean or with a few moist crumbs.
  7. Cool completely: Place the pan on a rack and let the cake cool fully before frosting, about 1 hour.
  8. Make the frosting: Beat the softened butter on medium-high until creamy and pale, about 2 minutes. Add powdered sugar in 2–3 additions, mixing on low at first, then increasing speed until fluffy.
  9. Adjust texture: Add heavy cream, vanilla, and a pinch of salt. Beat 1–2 minutes until smooth, light, and spreadable. Add more cream a teaspoon at a time if needed.
  10. Frost and decorate: Spread frosting over the cooled cake using an offset spatula. Add extra sprinkles on top. Slice into squares and serve.