Tag Archives: mermaid cake

Pastel Mermaid Tail Cake

Mermaids are definitely a big cake trend right now, and Cosmopolitan asked me to make a mermaid cake. The full video of this cake can be seen here. While there are a lot of different ways to make a mermaid cake, I think a mermaid tail is the most playful! Conveniently, it’s also the easiest!! My version of this cake was seven layers tall, but you could definitely scale this down to fewer layers. I used my go to vanilla cake batter and american buttercream recipe, listed below:

Vanilla Cake Ingredients:

  • 3 1/4 cup flour
  • 3 cups granulated sugar
  • 2 1/2 tsp baking powder
  • 1 tsp salt
  • 1 cup unsalted butter (2 sticks), room temperature
  • 3 tsp. vanilla extract
  • 1 cup egg whites (about 7 large egg whites)
  • 1 1/2 cups buttermilk, room temperature
  • 1/8 cup vegetable oil

American Buttercream Ingredients:

  • 6 sticks (2 cups) unsalted butter, room temperature
  • 12 cups powdered sugar
  • 1 tsp salt
  • 5 Tbsp. heavy cream
  • 3 tsp vanilla


  • light turquoise fondant
  • light blue fondant
  • light purple fondant
  • edible glitter


Preheat oven to 350°F. Grease and line four 7” round pans.

Mix together all dry ingredients (flour, baking powder, sugar, and salt) in a stand mixer with a paddle until fully combined.

Mix chunks of room-temperature butter slowly into the dry mix, on a low speed. Continue to mix until no large chunks of butter remain, and the mixture becomes crumbly.

Pour in egg whites, and mix on low until just incorporated.  Mix in the buttermilk in two installments, on a low speed. Add in vanilla and oil, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium high for about 30 seconds. Evenly divide that batter between three bowls, and color one light blue, one a light purple, and leave one uncolored (white).

Alternate cake batters (my color order blue, purple, white), and fill one 8 inch cake pan, two 7 inch cake pans, two 6 inch cake pans, and 2 four inch cake pans. I filled my cake pans about 1 inch full of batter. If you don’t have cake pans in those sizes, you can always make extra batter, and trim more cake away to get to the desired shape. For example, you could bake four 6 inch cake layers for the top of the cake, and trim away the top more.

Bake cake layers for 25-40 minutes, or until a skewer comes out clean. My 4 inch cake pans baked in about 25 minutes, and my 6 inch and 7 inch cake layers baked in about 32 minutes., and my 8 inch cake layer baked for about 35 minutes. Allow cake layers to cool for 10 minutes, then run an offset spatula around perimeter of the pan to separate the cake from the pan. Place cake layers on a rack to finish cooling.

While the cakes cool, prepare the frosting! Beat the butter on high for 30 seconds, until smooth. Slowly add in the powdered sugar, 1 cup at a time. Alternate with small splashes of cream. Once fully mixed, add in the vanilla and salt, and beat on medium low until the ingredients are fully incorporated, and the desired consistency is reached. If the frosting is too thick, add in cream (1 teaspoon at a time). If the frosting is too thin, add in more powdered sugar (quarter of a cup at a time). You can see a full tutorial on how to make this frosting here.

Assemble the cake layers largest to smallest, to build a cylindrical pyramid. Apply a thin layer of frosting between each layer with an offset spatula. Once all the cake layers are stacked, insert a tall wooden dowel into the cake layers. Place cake in freezer for about 5 minutes, to allow the cake to firm. Using a serrated knife, trim cake layers into the shape of a tail.


Apply a crumb coat of white frosting, and then chill the cake in the freezer for another five minutes. Once the crumb coat is firm to the touch, color the remaining frosting a light shade of turquoise. Apply a second layer of frosting, and smooth with a flexible smoother (bowl scraper or acetate sheet).


Using turquoise fondant mixed with tylose powder, shape a large mermaid flipper. Insert wooden skewers into the tail to attach it to the cake. For the scales of the tail, use a 1.5 inch circle cookie cutter, and cut out several circles from all three colors of fondant. Once the tail is firm, insert it on top of the cake.


Cover the cake in the circle scales, alternating all three colors, and working from top to bottom. Sprinkle edible gold dust onto the tail for an extra flourish of fun.I also used some leftover blue and white frosting to make waves around the base of the tail.

This cake requires a bit of work, but it’s totally worth it! It’s perfect for any mermaid fanatic, a kid’s birthday party, or if you just love pastels 🙂