Nothing screams “Summer” more than watermelon.  You can find me any day of the week stuffing my face full of fresh, juicy watermelon cubes, and I wanted to make a dessert to mirror my love for this refreshing treat.  Let me introduce you to my Watermelon Cake.


What is more appropriate to make a watermelon cake out of than Red Velvet Cake?  Well, red velvet with chocolate chip “seeds” of course!  I took my favorite sour cream red velvet cake and dressed it up just like a watermelon.  With green and red buttercream and even chocolate sprinkles, each slice of cake looks just like a slice of watermelon.


How to Make a Watermelon Cake:

1.   Prepare and bake Red Velvet Cake.  Trim tops of any domed cakes, if necessary.

2.  Place the bottom layer of cake on a cake board or turntable.


3.  Fill a pastry bag fitted with a medium, plain piping tip with buttercream.  Pipe a layer of buttercream onto the first layer of cake.  Even out buttercream with a small off-set spatula.


4.   Place the second layer of cake of top of the buttercream and repeat.


5.  Place the third cake layer on top, bottom facing up.

6.  Crumb coat the entire cake with a think layer of buttercream.


7.  Tint about 3/4 cup buttercream watermelon red.

8.  Place a large dollop of red buttercream on top of the cake.


9.  Carefully smooth out the red frosting on top of the cake with an off set spatula.  Be careful not to let any of the red frosting touch the sides of the cake.

10.  Tint about 1 1/2 cups buttercream green.  I made a leaf green and a lime green, then swirled them together – keeping the colors slightly under mixed and streaky like the outside of a watermelon.

11.  Fill a pastry bad fitted with a medium, plain round piping tip with the green buttercream.

12.  Starting at the bottom of the cake, begin piping flat rings around the sides of the cake.  This will help control the icing and help keep an even layer.  You do not need to pipe the thickness of the piping tip around the cake, a thinner layer will suffice.




13.  Be sure not to pipe any green frosting on the top of the cake.  Once the sides are covered, taking an icing smoother to smooth out the sides of the cake.



14.  Carefully transfer finished cake to a cake stand if desired.

15.  Place any remaining free frosting in a pastry bag fitted with a small, round tip.   Pipe a bead boarder around the bottom of the cake and the top where the red and green frostings meet.

16.  Finish off the top with chocolate sprinkles!



Red Velvet Cake


  • 1 1/4 cups all purpose flour
  • 1/4 cup cocoa powder
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon salt
  • 1/4 cup butter
  • 1/4 cup coconut oil
  • 1 cup sugar
  • 2 eggs
  • 1 teaspoon vanilla extract
  • 1/2 cup sour cream
  • 1/4 cup milk
  • red food coloring or red velvet emulsion
  • chocolate chips
  • For the buttercream - 3 egg whites
  • 1 cup sugar
  • 1 1/2 cups butter, softened
  • 1 teaspoon vanilla extract
  • red food coloring
  • green food coloring
  • chocolate sprinkles


  1. Pre-heat oven to 350 degree. Prepare 3 X 6" round baking pans and set aside.
  2. Sift together the dry ingredients and set aside.
  3. Place butter and coconut oil in the bowl of an electric mixer and mix until smooth.
  4. Add in the sugar and mix until fluffy.
  5. Add in the vanilla extract and eggs, one at a time.
  6. Mix together the milk and sour cream in a small mixing bowl.
  7. In alternating batches, add in the dry ingredients and the sour cream mixture with the mixer on low.
  8. Stir until just combined.
  9. Add in red food coloring or red velvet emulsion and mix to combine.
  10. Fold in the chocolate chips.
  11. Evenly distribute batter between the pans and bake until done (about 22-24 minutes).
  12. Cool on a wire rack for about 15 minutes before inverting.
  13. To make the buttercream, place egg whites and sugar in a clean bowl of an electric mixer.
  14. Whisk to combine.
  15. Fill a medium sauce pan with a couple inches of water and heat over medium.
  16. Place the mixing bowl on top of the sauce pan to create a double boiler.
  17. Heat egg mixture until it is hot to the touch (about 160-165 degrees on a candy thermometer)
  18. Once egg mixture is hot, transfer mixing bowl back to the mixer.
  19. Beat on high until the outside of the bowl returns to room temperature.
  20. Swap out the whisk for the paddle attachment.
  21. With the mixer on medium-low, add in the vanilla and butter, a few tablespoons at a time.
  22. Turn the mixer up to medium-high and mix until smooth.


20 Responses to How to Make a Watermelon Cake

  1. Tessa, you absolutely blow me away with your talent. This cake is stunning, I had to come over here after seeing the pic on your IG feed. All of these photos are amazing but my favourite is the very first photo in this post of the “slice” of watermelon on it’s side. So whimsical!

  2. tessssssaaaahhhh! this is the cutest most stylin’ watermelon cake i’ve ever SEEN! so adorable! xoxo

  3. sarah says:

    wow, this is gorgeous the way you presented it!! Whimsical and looks delicious

  4. Pang says:

    This is brilliant!!!!! So genius. So sweet of you to share this wonderful DIY with all of us.
    I LOVE LOVE LOVE this cake so so much.
    Thank you ..Thank you ..Thank you ..

  5. Oh MAN! I love this!!!!! That slice at the top. It is killing me!!!!!!

  6. Kelly Ward says:

    aHHHH! I am really going to try this one. It looks like I might be able to pull it off! I love reading your blog, Tessa. I am always inspired, but this one is going to make it to the kitchen. Happy Summer!!!

  7. I absolutely love your “how to” cake posts! The cakes always look INCREDIBLE and delicious!!! And your pictures are awesome!

  8. Brian says:

    I made your cake and let me tell you, my wife and child inhaled it. I didn’t even get a chance to try it lol

  9. Dani says:

    I whipped this cake up for the Fourth of July and everyone loved it! It was a huge hit with easy to follow instructions and the cake tasted great! I loved it! Super cute summer idea also :)

  10. […] interview since Peaches passed awayMust find someone to make this for me: Anyone want to make me this watermelon cake for my Birthday? […]

  11. […] from my experiments whether they be tips or mistakes.  In this case, the cake idea came from a pinterest post and it will be my honor to provide you with my avoidable mistakes and some helpful […]

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