Tulo

Unicorn Cake Recipe

Splitting one batter into six lightly tinted portions and baking them in thin layers gives a true rainbow cross-section without needing six separate recipes, and a chilled crumb coat keeps the pastel buttercream from smearing when the mane and horn go on.

Prep
60 min
Cook
45 min
Total
180 min
Servings
12

Ingredients

Servings12
  • 1 1/2 cups unsalted butter, softened (for cake)
  • 3 cups granulated sugar
  • 6 large eggs
  • 1 tbsp vanilla extract (for cake)
  • 4 1/2 cups all-purpose flour
  • 4 tsp baking powder
  • 1 tsp salt
  • 1 1/2 cups whole milk
  • 6 colors (few drops each) gel food coloring, assorted pastel colors
  • 2 cups unsalted butter, softened (for buttercream)
  • 6 cups powdered sugar
  • 4 tbsp heavy cream
  • 2 tsp vanilla extract (for buttercream)
  • 4 oz white fondant
  • 1 tsp edible gold luster dust
  • 1/4 cup rainbow sprinkles

Nutrition per serving

Calories
1179
Protein
10g
Carbs
156g
Fat
59g

Based on the recipe as written, one serving. Recalculates if you swap an ingredient above. An estimate only, exact values depend on the specific ingredients used.

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Instructions

  1. 1Preheat the oven to 350°F (175°C). Grease two 8-inch round cake pans, line the bottoms with parchment, and dust with flour.
  2. 2In a large bowl, cream the butter and granulated sugar together until pale and fluffy, 3-4 minutes. Add the eggs one at a time, beating well after each, then mix in the vanilla.
  3. 3Whisk the flour, baking powder, and salt together in a separate bowl. Add to the butter mixture in three additions, alternating with the milk, beginning and ending with the flour, and mixing just until combined.
  4. 4Divide the batter evenly among six bowls (about 1 1/4 cups each). Tint each bowl a different pastel color with gel food coloring, adding it a drop at a time until you reach the shade you want.
  5. 5Pour two colors of batter into the prepared pans and bake for 12-14 minutes, until a toothpick inserted in the center comes out clean. Cool 5 minutes, turn out onto a rack, then wipe out and re-grease the pans and repeat with the remaining batter in two more batches. Cool all layers completely.
  6. 6Make the buttercream: beat the butter until smooth, then add the powdered sugar in three additions, beating well after each. Beat in the cream and vanilla and whip on high for 2 minutes until light and fluffy.
  7. 7Level any domed cake layers with a serrated knife. Stack the six layers, spreading a thin layer of buttercream between each and alternating the colors so a cut slice shows a full rainbow.
  8. 8Coat the whole cake in a thin crumb coat of buttercream and refrigerate for 20 minutes, until firm to the touch, before adding the final coat.
  9. 9Frost the cake smooth on one side, then pipe pastel buttercream rosettes or swirls down the opposite side and over the top edge to form the mane.
  10. 10Shape a horn from the white fondant and let it firm up on the counter for 1-2 hours (or overnight), then brush it with gold luster dust mixed with a few drops of vodka or lemon extract until it's fully metallic. Insert the horn into the top of the cake between the mane and the front edge.
  11. 11Cut two ear shapes from fondant, tint the inner edges pink with a dry brush of pink dust, and press them into the cake on either side of the horn.
  12. 12Scatter rainbow sprinkles through the mane, chill the finished cake for 15 minutes to set the decorations, and bring to room temperature before slicing.
How to Frost a Cake

Tips & variations

  • Use gel food coloring, not liquid, for the rainbow layers; liquid coloring can thin the batter enough to change the bake time.
  • Shape and paint the fondant horn and ears a day ahead so they've fully firmed up before they need to hold their shape on the cake.
  • For an easier version, skip the six-layer rainbow and use just three tinted layers, or turn the same batter into 24 rainbow cupcakes and top each with a mini fondant horn.
  • If gold luster dust looks streaky, thin it with a few drops of clear alcohol like vodka rather than water, which can dull the metallic finish.

Storage & reheating

Store the finished cake loosely covered in the refrigerator for up to 4 days; the fondant pieces won't soften as long as they stay dry. Let slices sit at room temperature for 20-30 minutes before serving so the buttercream isn't stiff. Unfrosted, cooled cake layers can be wrapped individually in plastic and frozen for up to 2 months.

Tips from the Tulo kitchen

  • Bake the layers a day ahead and wrap them in plastic while still slightly warm, then refrigerate; cold layers are much easier to level and stack without crumbling.
  • A bench scraper held flat against the cake as it spins on a turntable gives a smoother final coat than a spatula alone.

FAQ

Can I use a box cake mix instead of making batter from scratch?

Yes. Two boxes of white cake mix will give enough batter to split into six tinted portions; just reduce the bake time slightly, since thinner layers bake faster than a standard two-layer cake.

Why did my fondant horn crack?

Fondant cracks when it's rolled too thin or dries too fast in a cold, dry room; work it slightly thicker at the base and let it firm up at room temperature rather than in the fridge.

How far in advance can I decorate the whole cake?

The frosted and decorated cake holds well in the refrigerator for up to 2 days before serving; add the sprinkles last so they don't lose their sheen sitting in the cold.

Can I make the rainbow layers without six bowls of batter?

Yes, use three colors instead of six and split each layer's batter in half to pour two thinner sub-layers per pan; you'll still get a striped effect with less bowl-washing.

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