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This watermelon cake is a fun summer dessert that looks and tastes just like a watermelon! All you need is white cake mix, watermelon Jello, and a handful of other ingredients to make it.

slice of watermelon cake being taken out with a cake spatula

If you were thinking this watermelon cake was made by carving up a big watermelon into the form of a layer cake, think again! While fresh watermelon is delicious, let’s be honest: it’s not exactly cake-level delicious. This recipe for watermelon cake takes the flavors of the fruit and infuses them into a layer cake!

watermelon cake served on a beige plate

Easy Watermelon Cake Recipe

When it comes to fun summer desserts, you really can’t beat this watermelon cake! The flavor makes you think of warm summer days, and it’s even decorated to look like a watermelon, making it extra fun!

You know I love a good boxed cake mix hack, and like my strawberry cake and coconut cream cake, this watermelon cake recipe starts with a box of cake mix. In this case, white cake mix makes the perfect base. We add watermelon Jello for flavor, color, and it also has the added bonus of making the cake super moist!

I use premade vanilla frosting, but cream cheese frosting will work too—basically, you’ll want to use something that can be tinted and that has a mild taste that won’t compete with the watermelon flavor, so you’ll want to avoid something like chocolate here.

ingredients to make watermelon cake

Ingredients

See recipe card below this post for ingredient quantities and full instructions.

  • White cake mix – Any brand you like will work!
  • Watermelon Jello
  • Water
  • Eggs – Here’s the best way to crack an egg!
  • Canola oil – Vegetable oil is fine, too.
  • Vanilla frosting – Use homemade or store-bought.
  • Red and green gel food coloring
  • Chocolate chips – You’ll use these to make the watermelon “seeds.”
steps to make watermelon cake

How to Make Watermelon Cake

1. Prepare

Preheat your oven to 350ºF and grease and flour two 9” round cake pans with butter or nonstick spray.

2. Make the Watermelon Cake Batter

In the bowl of a stand mixer fitted with the paddle attachment, combine the cake mix, Jello, water, eggs, and oil. Beat on medium speed until the mixture is smooth, which should take about 2 minutes. (You can use a hand mixer if you don’t have a stand mixer.)

3. Bake

Divide the batter between the prepared cake pans and bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean. Cool in the pan for 10 minutes, then carefully remove the cakes and place them on a rack to finish cooling. 

3. Make the Frosting

Set aside 2 tablespoons of frosting; this will be used for the white part of the watermelon. Place 1 ¼ cups of frosting in a bowl and tint it with the red coloring; start with a small amount and add more as needed to match the color of watermelon. Tint the remaining frosting green for the melon rind in a separate bowl.

4. Assemble

Place the first watermelon cake layer on a serving platter or cake stand. Frost the top with red frosting, leaving a ¼” border along the edge. Place the second cake layer on top and frost this with the remaining red frosting, leaving ¾” around the edge. Frost the edges of the cake green, then pipe the leftover white frosting where the red meets the green. Decorate the top of the cake with the chocolate chips. 

slice of watermelon cake served on a white round plate

How to Store Watermelon Cake

This cake should be stored in the refrigerator if it’s not eaten right away. I recommend wrapping it tightly with plastic wrap or placing it in an airtight container. It will stay fresh for 3-4 days; let it sit at room temperature for a few minutes before cutting into slices and serving.

You can also freeze this cake! Just wrap it tightly and place it in the freezer for up to 2 months. Let it thaw in the fridge overnight before serving.

slice of watermelon cake with frosting served on a white round plate with a forkful of cake

FAQs

How do you make a watermelon cake with whipped cream?

You could use a store-bought whipped cream or make homemade whipped cream and use that instead of the frosting. You can also use Cool Whip, which will last longer.

How do you make watermelon colored frosting?

To get the signature watermelon color, you’ll need to use red and green gel food coloring. Gel food coloring allows you to achieve the perfect shade of color without introducing excess liquid to the frosting!

Do you have to refrigerate watermelon cake?

Yes, this cake should be refrigerated to keep it fresh.

More Easy Cake Ideas

Watermelon Cake

This watermelon cake is a fun summer dessert that looks and tastes just like a watermelon! 
No ratings yet
Course: Dessert
Cuisine: American
Author: Kasey Schwartz
Prep Time: 30 minutes
Cook Time: 35 minutes
Total Time: 1 hour 5 minutes

Ingredients  

  • 1 box white cake mix
  • 1 3oz box watermelon Jell-O
  • 1 ¼ cups water
  • 2 large eggs
  • ¼ cup canola oil
  • 2 ½ cups vanilla frosting
  • red and green gel food coloring
  • chocolate chips for decoration

Instructions 

  • Preheat the oven to 350F. Grease and flour two 9” round cake pans.
  • In the bowl of a stand mixer fitted with the paddle attachment, add the cake mix, Jell-O, water, eggs, and oil. Beat on medium speed for 2 minutes until smooth.
  • Split the batter evenly between both prepared cake pans. Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean. Let cool in the pan for 10 minutes before removing and placing on a rack to finish cooling completely.
  • Set aside 2 tbsp of frosting for garnish. Place 1 ¼ cups of frosting in a bowl and tint with red coloring. Tint the remaining frosting green. Set aside.
  • Place one cake layer on a serving plate and frost the top with red frosting leaving a ¼” around the edge. Place the remaining cake on top and frost with remaining red frosting leaving ¾” around the edge. Frost the remaining areas of the cake with green. Pipe the leftover white frosting where the red meets the green on top. Decorate with the chocolate chips.

Nutrition

Calories: 4910kcal | Carbohydrates: 806g | Protein: 32g | Fat: 175g | Saturated Fat: 34g | Polyunsaturated Fat: 65g | Monounsaturated Fat: 71g | Trans Fat: 2g | Cholesterol: 327mg | Sodium: 4767mg | Potassium: 634mg | Fiber: 6g | Sugar: 575g | Vitamin A: 475IU | Calcium: 1207mg | Iron: 13mg
Keyword: cake, cake recipe, summer dessert
Did you make this recipe?Mention @kasey_allthingsmamma or tag #allthingsmamma!

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About Kasey Schwartz

Hi, I’m Kasey, Founder of All Things Mamma – where I am dishing up family favorite recipes that are easy to make with simple, everyday ingredients. Plus – tips and tricks for living your best life!

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