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Yields:
12 - 15 serving(s)
Prep Time:
20 mins
Total Time:
4 hrs
Let’s go over the top for St. Patrick’s Day this year with an epic top hat-shaped rainbow cake and a surprise Lucky Charm marshmallow center. I think we found our pot of gold! This cake, while it may take a lot of time, is very approachable. Once you start assembling the layers, the tricky part is done—just don’t forget to fill your cake with Lucky Charms before putting the top layer on! You’ll bake one layer in an 8" cake pan to create the rim of your hat, and you want this layer to be thinner than the rest. The other layers all use a 6" cake pan to easily create a top hat. You’ll be cutting out the centers of four of your cake layers, but no waste is needed! Turn those scraps into cake balls with any extra frosting you have and serve them alongside your cake.
This cake will definitely be the star of the show, but you still can’t leave out the corned beef and cabbage and Irish soda bread!
Did you try making this cake? Let us know how it went in the comments!
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Ingredients
Cake
Cooking spray
- 5 1/2 cups
(660 g.) all-purpose flour
- 1 Tbsp.
baking powder
- 1 tsp.
kosher salt
- 3 cups
(600 g.) granulated sugar
- 1 cup
(2 sticks) unsalted butter, softened
- 1 cup
vegetable oil
- 6
large eggs
- 1 Tbsp.
pure vanilla extract
- 1 cup
whole milk
- 1 cup
sour cream
Red, orange, yellow, green, blue, and purple food coloring, for decorating
Frosting & Assembly
- 8 cups
(920 g.) powdered sugar
- 2 1/2 cups
(5 sticks) unsalted butter, softened
- 1/3 cup
heavy cream
- 2 tsp.
pure vanilla extract
- 1/4 tsp.
kosher salt
- 1 1/2 cups
Lucky Charm marshmallows
Green, black, and yellow food coloring, for decorating
Directions
Cake
- Step 1Preheat oven to 350°. Line 1 (8") cake pan and 5 (6") cake pans with parchment; coat pans with cooking spray. In a large bowl, whisk flour, baking powder, and salt.
- Step 2In another large bowl, using a handheld mixer on medium-high speed, beat granulated sugar and butter until combined. Add oil and beat until smooth and creamy. Add eggs, one at a time, beating well after each addition, then beat in vanilla.
- Step 3Add about one-third of dry ingredients and beat on medium-low speed until just a few dry streaks remain. Add milk and beat until incorporated. Add another one-third of dry ingredients and beat on medium-low speed until just a few dry streaks remain. Add sour cream and beat until incorporated. Add remaining dry ingredients and beat until just combined.
- Step 4Divide batter among 6 bowls. Dye one bowl of batter red, one orange, one yellow, one green, one blue, and one purple.
- Step 5Pour purple batter into prepared 8" pan. Bake cake until a tester inserted into the center comes out clean, 15 to 18 minutes. Let cool.
- Step 6Pour remaining batters into prepared 6" cake pans. Bake cakes until a tester inserted into the center comes out clean, 30 to 35 minutes. Let cool.
- Step 7Make Ahead: Cake layers can be baked 1 day ahead. Wrap in plastic and refrigerate, or freeze up to 2 weeks.
Frosting & Assembly
- Step 1In a large bowl, using handheld mixer on medium speed, beat powdered sugar and butter until smooth. Add cream, vanilla, and salt and beat until combined.
- Step 2Trim tops of cooled cakes as needed. Using a 3" round cookie cutter, cut out center of orange, yellow, green, and blue cake layers.
- Step 3Place purple layer on a cake stand or platter. Frost top with a thin layer of buttercream. Top with blue cake layer. Frost with more buttercream and repeat with green, yellow, and orange cake layers in that order, frosting top of orange layer with buttercream. Pour marshmallows into center of cake. Top with red cake layer. Frost top and outside of cake with a thin layer of buttercream to create a crumb coat. Refrigerate until well chilled, at least 30 minutes or up to 2 hours.
- Step 4Scoop out about 1 1/2 cups buttercream. Dye remaining buttercream green. Using an offset spatula, frost cake with green buttercream, smoothing with a bench scraper.
- Step 5Divide reserved buttercream into about 1 cup and 1/2 cup. Dye 1 cup black and 1/2 cup yellow.
- Step 6Using offset spatula, frost a 1"-thick belt with black frosting at base of hat above the rim. To help create a smooth line, wrap cake in parchment above where you’ll frost, covering rim of hat with parchment as well.
- Step 7Transfer yellow buttercream to a piping bag fitted with a medium round tip. Pipe a buckle over belt.
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