Rainbow Sprinkle Cake with Classic Vanilla Frosting

Rainbow Sprinkle Cake is a nostalgic homemade vanilla sheet cake studded with rainbow sprinkles and finished with a colorful tie-dyed vanilla buttercream. Light, tender, and more satisfying than a box mix, this funfetti-style cake comes together quickly with about 30 minutes of hands-on prep.

Why You’ll Love This Recipe

• Better than boxed funfetti: fresh ingredients and real vanilla make a noticeable difference.
• Simple yet striking frosting: an easy tie-dye technique gives the cake a beautiful, colorful finish.
• Hassle-free sheet cake: baked in one 8-inch square pan—no crumb coats or layered cake work.
• Perfect for celebrations: great for birthdays, Pride events, or as a cheerful everyday treat.
• Fun and colorful: sprinkles in the batter and on top make each bite festive.

Recipe Ingredients

Key ingredients for this Rainbow Sprinkle Cake:

Ingredient Notes:

• Baking powder and baking soda: give lift for a light, tender crumb.
• Vegetable oil: keeps the cake moist better than butter alone.
• Vanilla extract: use pure vanilla for the best flavor.
• Lifeway Rainbow Cake Kefir: adds moisture and cake-like flavor; plain kefir or buttermilk can be used if unavailable.
• Rainbow sprinkles: jimmies or quins work best—use some in the batter and extra on top.

See the recipe card below for exact quantities and a complete ingredient list.

What Kind of Sprinkles to Use

Choose sprinkles that hold their color and won’t bleed into the batter. Jimmies (long cylindrical sprinkles) or quins (flat circles) are recommended. Avoid tiny nonpareils, which can bleed and lose definition when baked. Naturally dyed sprinkles look nice but may fade when mixed into batter.

Substitutions & Variations

• For a layered rainbow, divide the batter, tint portions with gel colors, and stack or swirl the layers.
• If Lifeway Rainbow Cake Kefir isn’t available, substitute plain kefir or buttermilk.
• Swap the vanilla buttercream for cream cheese frosting for a tangier finish.

If you try other swaps, adjust baking time and textures accordingly and share how it turned out.

How to Make a Rainbow Sprinkle Cake

Step 1: Preheat the oven to 350°F (175°C). Grease and line an 8-inch square pan with parchment paper.

Step 2: Whisk the dry ingredients (flour, baking powder, baking soda, salt) in a large bowl. In another bowl, whisk sugar, oil, vanilla, egg, and kefir together.

Step 3: Add the wet ingredients to the dry and mix until only a few streaks of flour remain. Stir in hot water, then fold in the sprinkles until just combined.

Step 4: Pour the batter into the prepared pan and bake on the middle rack at 350°F until a toothpick inserted in the center comes out clean, about 35–45 minutes. Let the cake cool in the pan, then remove to a wire rack.

Step 5: While the cake cools, make the buttercream by beating room-temperature butter, powdered sugar, and vanilla until smooth. Add a splash of milk or cream to reach the desired consistency.

Step 6: Spread the frosting over the cooled cake. Create the tie-dye effect by placing tiny drops of gel food coloring around the frosting and dragging a spatula or knife through the colors in short swoops. Top with additional sprinkles, slice into squares, and serve.

Rainbow Tie-Dye Frosting

The tie-dye look is simple: use gel food coloring so colors stay vibrant, dab very small drops of each color onto the white buttercream, then gently swirl with a spatula. Small, controlled motions keep the colors distinct and pretty.

Expert Baking Tips

1. Do not overmix the batter—stop as soon as ingredients are combined to keep the cake tender.
2. Use room-temperature ingredients so they combine smoothly and uniformly.
3. Weigh flour in grams with a food scale for consistent results rather than scooping from the bag.

Common Questions

Storage

Room Temperature

Store covered at room temperature in an airtight container for up to 3 days.

Refrigerator

Keep refrigerated in an airtight container for up to 1 week.

Freezing Instructions

Freeze the cooled cake, frosted or unfrosted, for up to 1 month. Thaw at room temperature before serving; refresh with fresh buttercream and sprinkles if desired.

More Recipes You’ll Love

Easy Rainbow Sprinkle Cake with Vanilla Frosting

Kayla Burton

Equipment

• 8×8 inch pan with parchment paper
• Mixing bowls
• Measuring spoons and cups or a scale
• Whisk
• Spatula

Ingredients

Rainbow Sprinkle Cake

• 1¾ cups (218.75 g) all-purpose flour
• ¾ teaspoon baking powder
• ¼ teaspoon baking soda
• ¾ teaspoon salt
• 1 cup (200 g) granulated sugar
• ½ cup (118 ml) vegetable oil
• 1 teaspoon vanilla extract
• 1 large egg, room temperature
• ½ cup (118 ml) Lifeway Rainbow Cake Lowfat Kefir (or plain kefir/buttermilk), room temperature
• ¼ cup (59 ml) hot water
• ⅓ cup (53 g) rainbow sprinkles (jimmies or quins)

Vanilla Buttercream

• ½ cup (113.5 g) unsalted butter, room temperature
• 2 cups (240 g) powdered sugar
• ¾ teaspoon vanilla extract
• 2 tablespoons milk or cream (adjust for consistency)

Instructions

1. Preheat oven to 350°F. Grease and line an 8-inch square pan with parchment paper.
2. In a large bowl, whisk together flour, baking powder, baking soda, and salt.
3. In a separate bowl, whisk sugar, vegetable oil, vanilla, egg, and kefir until combined.
4. Stir the wet ingredients into the dry until a few flour streaks remain. Add the hot water and mix until just combined.
5. Fold in the sprinkles gently. Pour batter into the prepared pan and bake on the middle shelf until a toothpick comes out clean, about 35–45 minutes.
6. Cool the cake in the pan, then transfer to a wire rack to finish cooling.
7. While the cake cools, beat butter, powdered sugar, vanilla, and milk until smooth. Adjust milk to reach spreading consistency.
8. Spread the buttercream over the cooled cake. For a tie-dye effect, add tiny drops of gel food coloring around the frosting and swoop with a spatula. Top with sprinkles, cut into squares, and enjoy.

Notes

Nutritional Information (estimate per serving)