Watermelon Pie

Name: Watermelon Pie
Cook time: 3 h 5 min
Total time: 3 h 5 min
Cuisine: American
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