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Ingredients
Scale
- 2 cups (248g) all-purpose flour
- 2 teaspoons baking powder
- ¾ teaspoon salt
- 1 cup (226g) unsalted butter, melted
- 1 ½ cups (300g) granulated sugar
- 4 large eggs
- 1 teaspoon vanilla extract
- 1 cup (237ml) buttermilk
- 1 cup (225g) rainbow sprinkles
- 1 cup (226g) unsalted butter, softened
- 4 cups (452g) powdered sugar
- 1 teaspoon (15 ml) vanilla extract
- ½ teaspoon salt
- 2–5 tablespoons (30-75ml) heavy whipping cream
- ½ cup (112g) sprinkles plus more for topping
Instructions
- Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
- In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
- In a large bowl, mix the melted butter and granulated sugar on medium speed until smooth. Add the eggs one at a time, mixing well after each addition, then blend in the vanilla extract.
- Gradually add the buttermilk, alternating with the dry ingredients, starting and ending with the buttermilk. Mix until just combined and scrape down the sides of the bowl to incorporate all ingredients. Stir in the rainbow sprinkles.
- Pour the batter into the prepared baking pan and bake for 30-40 minutes or until a toothpick inserted in the center comes out clean. Let the cake cool completely before frosting.
- For the frosting, beat the softened butter in a large bowl until creamy. Gradually add in the powdered sugar, one cup at a time, until a crumbly mixture forms. Mix in the vanilla extract and salt, then add 2 tablespoons of heavy cream and continue mixing until smooth. Adjust consistency with more cream if needed, and stir in additional sprinkles.
- Frost the cooled cake and top it with more sprinkles. Use an offset spatula for easy frosting. Store the cake loosely covered at room temperature for up to 2 days.
Notes
Ensure the butter is melted for the cake but softened for the frosting, as they require different textures.
Feel free to substitute the buttermilk with a mixture of milk and vinegar if needed.
This recipe can also be adapted to make cupcakes or layer cakes.
- Prep Time: 15 minutes
- Cook Time: 55 minutes
- Category: Desserts
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 slice
- Calories: 380
- Sugar: 43g
- Sodium: 200mg
- Fat: 16g
- Saturated Fat: 10g
- Unsaturated Fat: 4g
- Trans Fat: 0g
- Carbohydrates: 58g
- Fiber: 0g
- Protein: 3g
- Cholesterol: 70mg