Green Velvet Rainbow Cake

Mar 06

Tender green velvet cake layers with a rainbow vanilla buttercream, and a special surprise inside.

Got started on my St. Patrick’s Day cakes a little early this year and had so much fun making this Green Velvet Rainbow Cake – especially since I put a little surprise in the center for my kids.


For the cake, I adapted the Sweetapolita Red Velvet Cake I loved last year for Valentine’s Day. I omitted the red velvet emulsion, used green food gel and altered just a few other things here and there. I’ll have to admit, a green cake is a little strange to get used to (visually), but I do love the deep green color and it tastes just like a red velvet cake.

The best part of the cake is what’s inside. I decided to put a little gold at the end of this rainbow cake. I used 4-inch cookie cutters to cut out the centers from two of the cake layers. I then left two cake layers, the one for the bottom and the one for the top, completely whole, and filled the center with chocolate coins as I stacked the cake.


I loved cutting into this cake, probably more than the kids. It was so fun to see their reactions. Their eyes were glued to the cake as I cut, and they couldn’t hold their hands back as soon as they saw the coins fall out. Westin even told me, “Mom, that was really cool. I wasn’t expecting that!” Yes! Mom win!

Hope you enjoy this as much as we did!


Stay tuned for two more fun St. Patrick’s Day cakes!



Green Velvet Rainbow Cake

Yield One 4-layer, 6-inch round cake

Tender and moist green velvet cake layers with a rainbow vanilla buttercream.



  • 3/4 cup unsalted butter, room temperature
  • 1 cup light brown sugar, packed
  • 3/4 granulated sugar
  • 1 teaspoon green food gel (I use Americolor Gels)
  • 3 large eggs, room temperature
  • 2 1/2 cups all-purpose flour
  • 1 tablespoon cocoa powder
  • 1 teaspoon kosher salt
  • 1 1/2 cups buttermilk, warm
  • 1/4 cup sour cream
  • 1 tablespoon vinegar
  • 1 1/4 teaspoons baking soda


  • 2 cups unsalted butter, room temperature
  • 6 cups powdered sugar, measured and then sifted
  • 4 tablespoons heavy whipping cream
  • Dash of salt
  • 1 teaspoon pure vanilla extract
  • Americolor food gels, optional



  1. Preheat the oven to 350 degrees F. Spray the bottom and sides of four 6-inch round cake pans with nonstick spray, line the bottom with parchment paper, and spray again with the nonstick spray. Set aside.
  2. In a stand mixer fitted with the paddle attachment, combine the butter, granulated sugar, brown sugar, and green food gel. Beat the ingredients on medium-high speed for about 5 minutes, until the mixture is light in color and slightly increased in volume.
  3. Lower the speed and add the eggs, one at a time, mixing until each egg is incorporated before adding the next.
  4. In a separate bowl, sift the flour and cocoa powder. Sprinkle the salt on top of the dry ingredients and whisk until combined.
  5. With the stand mixer on low speed, alternately add the dry ingredients and the buttermilk into the butter mixture, beginning and ending with dry ingredients. Mix until just incorporated. Fold in the sour cream.
  6. In a small bowl, combine the vinegar and baking soda until it fizzes and then add to the batter. Whisk lightly until blended.
  7. Divide the batter evenly between the prepared pans (about 13-14 ounces of batter in each pan).
  8. Bake for 23-25 minutes. 
  9. Let pans cool on wire rack for about 10-15 minutes before inverting the cakes onto racks. Let cool completely.
  10. Level cakes. Use the cakes right away or wrap in plastic wrap and freeze for a few days. 


  1. In a stand mixer fitted with a paddle attachment, cream the butter on medium-high speed for about two minutes.
  2. With the mixer on low speed, slowly add the sifted powdered sugar until incorporated. Scrape down the sides of the bowl and continue to mix for another minute.
  3. Add the vanilla, salt and heavy cream (one tablespoon at a time). Once the cream is incorporated, increase the speed to medium-high and beat the frosting for five minutes. It should get lighter in texture and color.
  4. Divide the frosting into six bowls and add food coloring, if desired.
  5. Use a spoon to mix the frosting by hand, which will push out the air pockets created by the electric mixer.


  1. Once the cake layers are completely cooled and leveled, use a 4" cake ring or cookie cutter to cut the center of two cake layers out.
  2. Place the first cake layer (not one that has the center out) bottom-side down, in the center of the cake board. Using an offset palette knife, spread about 1/2 cup frosting evenly across the cake layer. 
  3. Place the second cake (one without a center) layer on top of the frosting. Frost the top of the second cake and add the third cake layer (the second cake without a center) on top of the frosting. Fill the center hole with gold coins and top with the final cake layer (which should be the second cake layer that wasn't cut out). 
  4. Crumb coat the entire cake with a thin layer of frosting and freeze for about 10 to 15 minutes to set.
  5. Once the crumb coat is set, continue to frost the cake with the remaining frosting.
  6. If you're doing the rainbow effect, place each color in it's own piping bag. Pipe two stripes of each color around the entire cake, starting with red at the top and finishing with purple at the bottom. Use a cake scraper to smooth out the colors and blend.

Leave a Reply

Your email address will not be published. Required fields are marked *