becky
This post may contain affiliate links. Please read the disclosure policy to learn more.
Thank you for supporting this blog!
Featuring pink chocolate chip watermelon buttercream sandwiched between a pair of whoopie pie cakes painted to look just like the striped green rind of a juicy watermelon, my miniature watermelon whoopie pies are a fun way to enjoy baking with watermelon, and a perfect summertime picnic treat!
Why Do I Love These Watermelon Whoopie Pies?
Growing up in central Pennsylvania, I developed a fondness for whoopie pies at an early age. Comprised of a pair of soft, dome-shaped round cakes with a creamy frosting sandwiched in between, whoopie pies are readily available for purchase at farmers markets, Amish bakeries, bake sales, and roadside farmstands throughout the state.
As an adult I moved to New York City, where whoopie pie options are few and far between. On the rare occasion that I did manage to locate them at a bakery or café, they often weren’t very good, or at least, not very authentic. (Luckily I soon discovered that Grow NYC Greenmarkets host vendors from Pennsylvania Dutch country. A trip to the greenmarket soon became a must-do weekend errand whenever I needed an authentic whoopie pie, shoo fly pie, or soft pretzel fix!)
But on days when I could’t make it to the greemarket, I’d make my own, great-tasting whoopie pies at home. The classic PA Dutch whoopie pie consists of a chocolate cake with vanilla filling, but there are also lots of fun variations, like red velvet whoopie pies and rainbow whoopie pies. So, why not watermelon? These miniature watermelon whoopie pies might not be “traditional” by any stretch of the imagination, but they’re fun to make, and delicious, too!
Special Tools and Ingredients for Making Watermelon Whoopie Pies
These watermelon whoopie pies require a few special tools and ingredients. To make this miniature whoopie pie recipe, you’ll want to begin by gathering the following:
- Disposable Piping Bags – You’ll want to have disposable piping bags on hand for piping the cakes, as well as the buttercream. You’ll also need a set of round piping tips.
- Food-Safe Paint Brushes – You can purchase regular paintbrushes from a craft store, or special cake decorating brushes. Whichever you choose, you’ll need to keep these completely separate from any painting or craft supplies. (I keep my brushes in a zippered plastic case, alongside my food colorings and flavorings.) Never use brushes which have been previously used with artists’ paints.
- Gel Food Coloring – Be sure to use gel food colorings for this recipe, rather than the water-based kind found in grocery stores. I used Neon Brite Pink for the buttercream, Neon Brite Green for the cake batter, and Leaf Green for the stripes.
- Miniature Chocolate Chips – Miniature chocolate chips are a must. Full-size chips will clog your piping bag, and also make it difficult to sandwich the buttercream between the two cakes. If you can’t find miniature chocolate chips, finely chopped chocolate works just as well.
- Watermelon Flavoring – Gives the buttercream its distinctive flavor. I used LorAnn Oils watermelon flavoring.
Notes on Watermelon Buttercream
The watermelon buttercream should be smooth and creamy, but still firm enough to pipe. Add more cream or confectioner’s sugar as needed to adjust the consistency of the buttercream.
As written, this recipe makes enough watermelon buttercream to fill each whoopie pie with a thick layer of frosting, plus some left over. You can halve the buttercream recipe if you prefer less filling.
Be sure to use miniature chocolate chips, not full-size baking chips! See my notes above.
Piping Watermelon Whoopie Pies
Standard whoopie pies are usually about 4 inches or so in diameter. I made these in miniature size (after baking, each cake is about 2 inches round) because the filling is fairly sweet. But, feel free to pipe your cakes in any size you’d like.
Make-Ahead and Storage Suggestions
I suggest baking the cakes on the day you plan to serve your watermelon whoopie pies. Although they will keep reasonably well for a couple of days, they’re freshest and moistest on the day they’re made.
You can prepare the watermelon buttercream up to 24 hours in advance. Cover the bowl and refrigerate until ready to use, or scoop the buttercream into a piping bag and refrigerate. Allow the buttercream to soften at room temperature for 30-60 minutes before piping.
To store, layer leftover whoopie pies between sheets of parchment and place in an airtight container at room temperature. You can also wrap the individual cakes in clingfilm/plastic wrap for an easy, on-the-go treat.
Other whoopie pie recipes you might enjoy:
Lemon Whoopie Pies
Raspberry Mojito Whoopie Pies
Rainbow Whoopie Pies
Red Velvet Whoopie Pies
And if you make these, or any of my recipes, don’t forget to tag me @bastecutfold or use the hashtag #bastecutfold on Instagram. I always love to see what you’re making!
Mini Watermelon Whoopie Pies
Miniature watermelon whoopie pies filled with chocolate chip watermelon buttercream.
- Prep Time: 40 minutes
- Cook Time: 8-10 minutes
- Total Time: 50 minutes
- Yield: 30 2-inch whoopie pies 1x
- Category: Whoopie Pies
- Method: Oven
- Cuisine: Desserts
Ingredients
Cakes:
400 grams all purpose flour (3 1/8 cups)
1 teaspoon baking soda
1 teaspoon baking powder
1/2 teaspoon salt
210 grams granulated sugar (1 cup)
113 grams unsalted butter, softened (1/2 cup / 1 stick)
1/2 teaspoon vanilla bean paste
1 large egg, at room temperature
240 milliliters whole milk (1 cup)
Light and dark green gel food colorings
Buttercream:
115 grams unsalted butter, softened (1/2 cup / 1 stick)
750 grams confectioner’s sugar (6 cups)
5 tablespoons whole milk or whipping cream, plus more to adjust consistency
Pinch salt
1/4 teaspoon watermelon flavor oil (or to taste)
3–4 drops pink gel food coloring
200 grams miniature chocolate chips*** (1 cup)
Instructions
Cakes:
Preheat oven to 400° F / 205° C. Line two baking trays with silicone mats, and set aside until ready to use.
In a large bowl, combine the flour, baking soda, baking powder, and salt. Set aside.
In a separate mixing bowl or the bowl of a stand mixer, whip butter, sugar, and vanilla bean paste on high speed until light and fluffy. Add the egg and mix until well combined.
In 3-4 additions, add the dry ingredient mixture to the batter, followed by the milk. Mix until well combined.
Add the light green food coloring, a few drops at a time until the desired shade is achieved. (Be careful not to go too dark–you want the cakes to be light enough to create a contrast with the dark green lines you’ll be painting on top!)
Transfer batter to a piping bag. Pipe 1.25-inch / 3-centimeter rounds on prepared trays, allowing a good amount of space in between. With damp fingertips, pat down the tops of each cake to create a smooth, evenly domed surface.
Ina small bowl, mix a few drops of dark green gel food coloring** with a drop or two of water. (The consistency should be smooth, but still somewhat thick. If the mixture is too watery, it will bleed when applied to the cakes.) Using a thin paintbrush, paint “watermelon” lines on the top of each cake.
Bake in preheated oven for 8-10 minutes, or until cakes are just beginning to brown around the edges. Do not overbake.
Transfer to a wire rack and allow to cool completely before filling.
While cakes are baking and cooling, prepare the watermelon buttercream.
Buttercream:
In a large mixing bowl or the bowl of a stand mixer, whip butter until light and fluffy. Gradually add the icing sugar, mixing well after each addition. Mix in the milk/whipping cream and a pinch of salt, then whip until smooth and creamy, about 3-5 minutes. If necessary, add a bit more cream or icing sugar to adjust the consistency.
Add the pink food coloring and the watermelon flavoring, adjusting as necessary until desired color and flavor are achieved.
Using a wooden spoon or rubber spatula, gently fold chocolate chips into the buttercream.
When cakes have cooled, transfer watermelon buttercream to a piping bag. Pipe a generous amount of buttercream on the flat side of one cake, then top with another cake to create a sandwich.
Store watermelon whoopie pies in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to one week. Be sure to add sheets of parchment or wax paper between layers to prevent the cakes from sticking together. Alternately, you can wrap each individual pie in clingfilm/plastic wrap for freshness and convenience.
Notes
*As written, this recipe makes enough to fill each whoopie pie with a generous amount of buttercream, plus some extra (I used the leftovers to make watermelon macarons!) Recipe can be halved if you prefer less filling.
**Be sure to use gel food coloring for this recipe, rather than the water-based kind found in grocery stores.
***Miniature chocolate chips are a must for this recipe–full-size chips will clog the piping bag, and make it difficult to sandwich your buttercream between the two cakes. If you can’t find miniature chocolate chips, finely chopped chocolate will work just as well.