Pin A playful, moist, and colorful sheet cake designed to celebrate any occasion & deliciously homemade, with charmingly imperfect swirls of frosting and sprinkles.
The first time I made this birthday sheet cake, my friends were delighted by the bright swirls and cheerful sprinkles. It became an instant tradition at our celebrations, especially because nobody had to fuss about creating a flawless appearance & the fun is all in the imperfections.
Ingredients
- All-purpose flour: 2 1/2 cups (325 g)
- Granulated sugar: 2 cups (400 g)
- Baking powder: 1 tablespoon
- Salt: 1/2 teaspoon
- Whole milk: 1 cup (240 ml), room temperature
- Unsalted butter (cake): 3/4 cup (170 g), melted and slightly cooled
- Large eggs: 4, room temperature
- Vanilla extract (cake): 2 teaspoons
- Sour cream: 1/2 cup (120 ml), room temperature
- Unsalted butter (frosting): 1 cup (225 g), softened
- Powdered sugar: 4 cups (480 g), sifted
- Whole milk (frosting): 1/4 cup (60 ml), more as needed
- Vanilla extract (frosting): 2 teaspoons
- Salt (frosting): Pinch
- Food coloring: Assorted colors, optional
- Rainbow sprinkles: 1/3 cup (60 g)
Instructions
- Prepare Cake Pan:
- Preheat oven to 350°F (175°C). Grease and line a 9x13-inch (23x33 cm) sheet pan with parchment paper.
- Make Cake Batter:
- In a large bowl, whisk together flour, sugar, baking powder, and salt. In a separate bowl, whisk milk, melted butter, eggs, vanilla, and sour cream until smooth.
- Combine Ingredients:
- Pour wet ingredients into dry ingredients and stir until just combined. Do not overmix.
- Bake:
- Transfer batter to prepared pan and smooth the top with a spatula. Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean.
- Cool:
- Cool cake completely in the pan on a wire rack.
- Make Frosting:
- Beat softened butter until creamy. Gradually add powdered sugar, mixing well. Add milk, vanilla, and salt & beat until fluffy. If desired, divide frosting and tint with food coloring.
- Decorate:
- Dollop or swirl frosting onto cooled cake using a spatula, embracing imperfect swirls and texture. Scatter generously with rainbow sprinkles.
- Serve:
- Slice and serve directly from the pan.
Pin 
Every year, my family gathers to enjoy this sheet cake & kids especially love helping with the imperfect swirls and tossing on the sprinkles together.
Required Tools
You will need a 9x13-inch (23x33 cm) sheet pan, mixing bowls, whisk, spatula, electric mixer (optional), and parchment paper.
Notes
For a chocolate version, substitute 1/2 cup flour with cocoa powder or swap sour cream for Greek yogurt if preferred. Store leftovers covered at room temperature for up to 2 days or refrigerate for up to 5 days.
Nutritional Information
Per serving: Calories 410, Total Fat 18 g, Carbohydrates 59 g, Protein 4 g.
Pin This cake brings joyful color to every celebration & tastes just as delightful as it looks. Enjoy each imperfect slice with laughter and sprinkles!
Recipe Questions & Answers
- → How do I achieve a moist cake texture?
Use whole milk, sour cream, and melted butter as in this method. Mix ingredients just until combined to avoid dryness.
- → Can I color the frosting differently?
Absolutely! Divide the frosting and use assorted food coloring for vibrant swirls and playful appeal.
- → Is it necessary to use sprinkles?
No, but rainbow sprinkles add festive color. You can leave them out or substitute with chopped nuts or chocolate chips.
- → How do I store the leftover cake?
Keep the cake covered at room temperature for up to 2 days or refrigerate for up to 5 days for freshness.
- → Can I make a chocolate version?
Swap out 1/2 cup of flour for cocoa powder to turn this dessert into a chocolate treat—delicious and easy!
- → What tools are recommended for preparation?
A 9x13-inch sheet pan, mixing bowls, whisk, spatula, and optional electric mixer will simplify the process.