This is a watermelon cake inside and out! I used real watermelon to flavor this cake and then used buttercream to create a simple design on the outside. Fun and delicious!


A watermelon cake inside and out!
5 from 2 votes

Watermelon Cake

Prep Time 30 minutes
Cook Time 30 minutes
Total Time 1 hour
This is a watermelon cake inside and out! I used real watermelon to flavor this cake and then used buttercream to create a simple design on the outside. Fun and delicious!


  • 2 cups (226g) all-purpose flour sifted
  • 1 ¼ cup (250g) granulated sugar
  • 1 tbsp. baking powder
  • 1 tsp. salt
  • ½ cup 1 stick, 113g butter, softened
  • 1 cup watermelon juice*
  • 1 tsp. McCormick® Strawberry Extract or more to taste
  • 2 eggs room temperature
  • 1/2 tsp. McCormick® Red Food Color
  • 1 1/2 cups mini semi-sweet chocolate chips divided (and 1 tablespoon flour for sifting)


  • Preheat oven to 350°F. Grease and flour two 8-inch round cake pans.
  • In a large mixing bowl sift together flour, sugar, baking powder and salt.
  • Make a well in the center and add butter, watermelon juice, strawberry extract, eggs, and red food color. Beat with a hand mixer on medium speed for about 1 minute, or until ingredients are fully incorporated.
  • Sift 1 cup of chocolate chips with 1 tablespoon flour and then gently stir into batter.
  • Pour batter into prepared pans, dividing equally among both. Equally divide about 1/4 cup chocolate chips between the two cake pans. (The remaining chocolate chips will be used between the layers of the cake when you frost it.) Bake 20 to 30 minutes or until a toothpick comes out mostly clean.
  • Cool in pans on wire racks. When cakes have cooled completely, turn out onto wire racks.
  • * To make watermelon juice, simple cut about 1/4 a medium size watermelon into chunks. Place in blender and puree until smooth.

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A watermelon cake inside and out!

Watermelon Cake

I wanted to create a from-scratch watermelon cake that had a fun design inside as well as out! A few simple ingredients are all you need to recreate this summertime cake that is perfect for any party and 4th of July barbecue!!

To make this cake you will need:

Watermelon cake recipe (below)

vanilla buttercream

red, green, and black McCormick® Food Color

pastry bag

#3 tip

small offset spatula

cake stand

This juice went into a cake batter to make watermelon cake!

Begin by making the cake.

You will notice that I add watermelon juice to the batter. This is simply watermelon that I have pureed in the blender!

Add strawberry extract to a from-scratch watermelon cake for extra special flavor!

You may also notice that I added a bit of McCormick® Strawberry Extract. I found that when I added just a little it seemed to enhance the watermelon flavor. I also believe there is something about “eating with our eyes”, so when people bite into this cake, they tend to match the sweet “berry” flavor to that of a watermelon. It’s quite fascinating!

After cakes have baked, allow them to cool.

Prepare vanilla buttercream.

I separated my frosting into 2 bowls. The first bowl I tinted a light green. (about 3 drops of McCormick® Green Food Color.) The other bowl I then divided again.

Tinting frosting red for a watermelon cake!

One portion was tinted red with McCormick® Red Food Color. I used about 2 teaspoons. The final portion of buttercream was tinted a dark green, I used about 2 teaspoons here as well. After I piped the green lines on the cake (I will show you how in a moment) I tinted the remaining green frosting black. Because it was already dark, I used very little black food color.

Matching frosting to cake and building a watermelon cake!

Set the first layer of cake on cake stand. Evenly spread about 1/2 cup of the red buttercream over the top of the cake.First layer of watermelon cake with frosting and mini chocolate chips!

Place other layer of cake on top.

Spread about 1/2 cup of red buttercream around the top of the cake and smooth as much as possible.

Now spread a thick layer of the light green buttercream around the sides of the cake. You may need to do a crumb coat, chill the cake, and add more light green. You do not want to see the cake underneath or crumbs in the frosting.

How to create a buttercream watermelon effect on a 2-layer cake!

Now take your dark green and make a vertical line on the side of the cake. I did 3 lines at a time and spaced them about 1/2 apart. I then tool an offset spatula and pressed into the green line, moving up. The goal is to get the line to blend seamlessly with the light green frosting and also to create a rough line, not one with perfect edges. (just think how a watermelon looks)

When swiping up I would also then remove the excess frosting from my spatula so as to not smear the next line too much.

Do this around the entire cake.

When done, carefully go around the entire cake and smooth out the top edge.

Made with all buttercream, this fun watermelon cake looks like watermelon on the outside!

Now get your black buttercream and put it into a pastry bag fitted with a #3 small round tip. Pipe out little black seeds around the top of the cake. You can do as many as you want and any size you want! If you want to make one row of seeds but slightly bigger, I would switch to a #5 or #7 tip.

Slice of buttercream watermelon cake!

If you want a nice clean crisp slice, chill the cake before cutting. The cake tastes great at room temperature as well as chilled.

Delicious slice of watermelon cake!

Tips for success:

Using freshly pureed watermelon juice works best.

I tried to match my red buttercream to the color of the cake. This works best if you tint your buttercream after the cake is baked.

Be sure to sift the mini chocolate chips in flour so that they do not all sink to the bottom of the cake. I also added a few on top of the batter just before baking.

Slice of a cake that is decorated to look like a watermelon inside and out!

I hope you love this From-Scratch Watermelon Cake recipe! Want other tips and tricks to make a flavorful 4th of July? Check out McCormick’s recommendations a delicious no bake treat like Firework Poke Cake or Chocolate Chip Cookie Dough Stars.



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Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. This is an exciting cake for a summer party. I may try it for a party this week. I have LorAnns Watermelon Oil that I’m going to try in place of the Strawberry Extract.

  2. That watermelon cake is the food of champions! Dying to eat this! Thanks for posting it, Amanda!

  3. I’m going to attempt this next weekend, but I’m pressed for time with a toddler on my heels. Is there any chance I could cheat just a little and use a white cake box mix instead? Sacrilege, I know!

  4. Tasted like candy, not cheap candy!! I like that this is asking for strawberry extract because watermelon flavored ones are pretty gross. I liked this recipe alot. A friend of mine is doing one in a melon theme for here daughter that’s turning 1. I Recommend to try

  5. Amazing looking cake!
    Can I make ahead of time & freeze (like mud cakes)?
    If not how far ahead of the party can I make it with it staying fresh?

    Thank you.

  6. This is my daughters favorite cake, I have made it for years, but lost my recipe. Thank you for helping me find it. I am making this for her wedding cake this summer!

  7. I first tried the watermelon cake mix and it was delicious but I can’t find it no more but I try this thank you so much

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