Funfetti Cake
A soft, fluffy vanilla funfetti cake made with upgraded cake mix, layered with silky vanilla buttercream and overflowing rainbow jimmies hidden inside every slice. This easy semi-homemade recipe transforms a simple boxed mix into a bakery-style celebration cake with rich flavor, extra moisture, and the perfect dramatic sprinkle center.
Equipment
- 3 8-inch cake pans
- Stand mixer or hand mixer
- Serrated knife or cake leveler
- Round cookie cutter or glass for center holes
Ingredients
Funfetti Cake Layers
- 2 box Bob's Red Mill Vanilla Yellow Cake Mix
- 1 additional cup cake flour
- 8 large eggs
- 2 cups whole milk
- 1 cup neutral oil
- 1 1/2 cups rainbow jimmies sprinkles
Sprinkle Center Filling
- 2 cups rainbow jimmies sprinkles
Vanilla Buttercream Frosting
- 4 sticks 2 cups unsalted butter, softened
- 6-7 cups powdered sugar
- 1/3 cup hot water
- 2 teaspoons vanilla bean paste
- 1/2 teaspoon salt
Instructions
Make the Cake Layers
- Preheat the oven to 350°F (175°C). Grease and line three 8-inch cake pans with parchment paper.
- In a large mixing bowl, whisk together the cake mix, cake flour, and salt.
- Add the eggs, whole milk, sour cream, melted butter, oil, and vanilla bean paste. Mix until smooth and fully combined.
- Gently fold in the rainbow jimmies sprinkles, being careful not to overmix.
- Divide the batter evenly between the prepared cake pans.
- Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.
- Let the cakes cool in the pans for 10–15 minutes before transferring to wire racks to cool completely.
Make the Hot Sugar Buttercream
- In a medium bowl, whisk together the powdered sugar and hot water until smooth and glossy. The mixture should resemble a thick glaze.
- In a stand mixer fitted with the paddle attachment, beat the softened butter on medium-high speed for 5–7 minutes until extremely pale, light, and fluffy.
- Slowly pour the warm sugar mixture into the whipped butter while mixing on low speed.
- Add the vanilla bean paste and salt, then continue whipping for another 3–4 minutes until smooth, silky, and airy.
Assemble the Cake
- Level the cake layers if necessary.
- Using a round cutter or glass, cut a hole in the center of the two bottom cake layers. Leave the top layer whole.
- Place the first cake layer onto a cake stand or serving plate and spread an even layer of buttercream on top.
- Add the second hollowed layer and frost the top again.
- Fill the center cavity generously with rainbow jimmies sprinkles until completely full and slightly overflowing.
- Place the final full cake layer on top to seal in the sprinkle center.
- Frost the outside of the cake with the remaining buttercream.
- Decorate with extra sprinkles around the edges and top of the cake if desired.
Notes
Cozy Baking Tips
- Only use jimmies sprinkles in the batter to prevent color bleeding.
- Chill the cake layers before assembling for cleaner frosting.
- Use room temperature ingredients for the smoothest batter.
- For extra clean slices, chill the assembled cake for 20–30 minutes before cutting.
- Store the cake covered at room temperature for up to 2 days or refrigerated for up to 5 days. Let slices come
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