Watermelon Pie Recipe

Active Time:

35 mins

Chill Time:

2 hrs 30 mins

Total Time:

3 hrs 5 mins

Servings:

Is there anything more refreshing on a hot summer day than biting into a chilled slice of watermelon? Now imagine that sweet, cooling flavor in a dreamy dessert. This charmingly retro watermelon pie classically made with watermelon-flavored gelatin has been upgraded with fresh watermelon, so it has all of the fruit's natural sweetness and flavor.

A Biscoff cookie crust lends notes of caramel and brown sugar to the pie, while bright lemon zest and the light tang of mascarpone cheese balance the sweetness. The topping, a mixture of heavy cream and mascarpone, is light and creamy without melting as easily in the summer heat.

Your guests will love cooling down with a slice of this watermelon pie. The best part? There's no need to turn on the oven for this dessert. All components are mixed and chilled so you can keep the heat outside where it belongs.

Ingredients for Watermelon Pie

To make this pie, you'll need a few key ingredients:

Cookies: For the crust, grab your favorite crisp cookies (we like Biscoff).
Salt, sugar, and melted butter round out the crust.
Watermelon: The filling calls for fresh watermelon—you'll puree some and ball up the rest.
Tapioca: You'll need quick-cooking tapioca for thickening the filling.
Sugar, lemon zest, and lemon juice are in the filling, too.
Food coloring: A couple of drops of red food coloring helps accentuate the filling's dreamy, pink color (though it's optional if you want to skip it).
Heavy cream and mascarpone lighten the mix.
Powdered sugar: Sweetens the topping.

How To Make Watermelon Pie

Full instructions for making a watermelon pie are below, but here's a brief recap before you get started:

Step 1. Start with the cookie crust: Crisp cookies are processed with salt, sugar, and butter and pressed into a 9-inch pie plate before chilling.
Step 2. Prepare the watermelon filling: Pureed watermelon is mixed with finely ground tapioca and sugar, and heated until the tapioca dissolves. The mixture thickens as it stands for about 20 minutes and then lemon zest, lemon juice, and red food coloring, if using, are mixed in.
Step 3. Combine watermelon and whipping cream mixtures: The watermelon mixture gets folded into a combination of whipped heavy cream, mascarpone, and powdered sugar, and poured into the prepared crust.
Step 4. Refrigerate: Chill for at least two hours before topping with remaining whipped cream, mascarpone, and powdered sugar, along with decorative, halved watermelon balls.

Can Watermelon Pie Be Made Ahead?

Watermelon Pie is best served on the day it's prepared. The whipped filling and topping will break down over time.

But if you'd like to make components ahead, the cookie crust can be prepared and chilled or frozen up to a week in advance. The watermelon can be balled and pureed, and the filling made and set in the crust a day in advance. Finish with the whipped topping on the day of serving.

Ingredients

2 1/2 cups crumbled crisp gourmet cookies (such as Biscoff; from 1 [8.8-oz.] pkg.)
1/2 teaspoons kosher salt
1/2 cup plus 2 Tbsp. granulated sugar, divided
6 tablespoons unsalted butter, melted
1 (7 1/2-lb.) seedless watermelon
1/2 cup uncooked quick-cooking tapioca (such as Kraft Minute Tapioca)
1 tablespoon lemon zest plus 1 Tbsp. fresh juice (from 1 lemon)
1 - 2 drops red food coloring gel (optional)
2 cups heavy cream, divided
1 (8-oz.) container mascarpone cheese, divided
1/2 cup plus 1/3 cup powdered sugar, divided

Directions

Make pie crust:

Heavily coat a 9-inch pie plate with cooking spray; set aside. Place crumbled cookies, salt, and 2 tablespoons of the granulated sugar in a food processor, and process until finely ground, 10 to 15 seconds. Add melted butter; process until mixture is moist and clumps together easily, about 5 seconds. Press crumb mixture evenly on bottom and up sides of greased pie plate. Refrigerate until set, about 30 minutes.
Blend watermelon for juice:

Cut part of the watermelon into cubes to equal 3 cups (about 16 oz.). Cover remaining watermelon with plastic wrap, and refrigerate until ready to use. Place cubed watermelon in a blender, and process until smooth, about 20 seconds. Pour through a fine wire-mesh strainer into a large measuring cup, pressing gently to squeeze out juice; discard solids. (You should have about 1 1/2 cups of watermelon juice.)
Grind tapioca:

Place tapioca in a spice grinder or coffee grinder; process until finely ground, about 40 seconds. Sift ground tapioca through a fine wire-mesh strainer into a small bowl. Set aside 2 tablespoons plus 1 teaspoon of the tapioca powder. (Reserve remaining tapioca powder for another use.)
Make pie filling:

Stir together watermelon juice, 2 tablespoons plus 1 teaspoon tapioca powder, and remaining 1/2 cup granulated sugar in a small saucepan; let stand 5 minutes. Bring to a boil over high, and cook, whisking often, until tapioca dissolves, 5 to 6 minutes. Immediately remove watermelon mixture from heat. Let stand, stirring occasionally, until thickened, about 20 minutes. Stir in lemon zest, lemon juice, and (if desired) 1 to 2 drops food coloring gel.
Add whipped cream mixture to watermelon filling:

While watermelon mixture stands, beat 1 cup of the heavy cream and 1/4 cup of the mascarpone with an electric mixer fitted with whisk attachment on high speed until soft peaks form, about 50 seconds. Gradually add 1/2 cup of the powdered sugar, beating until stiff peaks form, about 10 seconds. Working in batches, gently fold watermelon mixture into whipped cream mixture until smooth and blended. Spoon watermelon mixture into prepared pie plate. Refrigerate until firm, about 2 hours.
Make watermelon balls:

Scoop out flesh of remaining watermelon with a sharp 1-inch melon baller, making about 10 (1-inch) balls. Cut watermelon balls in half, and place, cut side down, on a plate lined with paper towels; set aside.
Make topping:

Gently stir together remaining mascarpone cheese and 1/3 cup powdered sugar in a large bowl just until combined. Beat remaining 1 cup heavy cream in a medium bowl on medium speed until stiff peaks form. Gently fold whipped cream into mascarpone mixture.
Finish pie:

Dollop mascarpone-whipped cream topping on top of pie, leaving a 1-inch border. Place watermelon-ball halves, cut side down, along edges of whipped cream topping. Serve immediately.

Frequently Asked Questions

What other types of cookies can I use for a cookie crust?

Any crisp cookie will do nicely here, including shortbread, lemon cookies, or vanilla wafers. You can also grab a store-bought graham cracker crust in a pinch.
How do I know if my watermelon is ripe?

There are a few quick tips when it comes to picking a ripe watermelon. Look for melons that are dark in color and with a dull (not shiny) rind. It should feel heavy for its size, echo back a "thump" when tapped, and have some sugar spots, or webbing, on its surface.
Can I use gelatin instead of tapioca starch?

Certain watermelon pie recipes rely on gelatin to help set the filling for clean slicing. This filling is thickened with tapioca and has not been tested with gelatin.
How should I store watermelon pie leftovers?

Leftover watermelon pie can be refrigerated in an air-tight container for one to two days. The filling and topping will begin to break down over time.