Cut watermelon into large chunks. To a blender, add watermelon chunks and process until smooth, about 20 seconds. Strain through a fine-mesh sieve into a large liquid measuring cup, aiming for 1 cup watermelon juice. Discard solids and save any extra juice for another use.
To a large heatproof bowl, add 1/4 cup watermelon juice. Sprinkle gelatin over watermelon juice and let sit to bloom for 5 minutes. Meanwhile, in a small saucepan, heat 1/2 cup watermelon juice on medium until steaming, about 1 to 2 minutes. Do not boil juice. When steaming, add hot watermelon juice to gelatin mixture and whisk to dissolve gelatin. Add salt, 2 to 3 drops food coloring, if using, and remaining 1/4 cup watermelon juice. Stir until combined and allow to cool completely.
Meanwhile, in a large bowl, combine 1 cup heavy cream, 1/2 cup marshmallow fluff and 1 tablespoon confectioners' sugar. Beat with an electric mixer on high until stiff peaks form, about 3 minutes. Add 1/3 whipped cream mixture to cooled watermelon mixture and fold to combine. Add watermelon mixture to remaining whipped cream mixture, and gently fold until smooth. Transfer filling to graham cracker crust. Refrigerate 1 hour, until firm.
When ready to serve, combine remaining 1 cup heavy cream, 1/2 cup marshmallow fluff and 2 tablespoons confectioners' sugar in a large bowl. Beat with electric mixer on high until stiff peaks form, about 3 minutes. Pipe marshmallow whipped cream on top of pie, leaving a 1" border. Slice and serve.
Source: Hannaford fresh Magazine, July August 2024