Spray a 14x4-inch removable-bottom tart pan with cooking spray.

Prepare Homemade Graham Cracker dough through step 1. Roll dough into a 15x5-inch rectangle. Transfer to prepared pan, pressing into bottom and up sides. Poke holes with a wooden pick along bottom and sides.

Bake for 15 minutes. Let cool completely.

Pour Chocolate Ganache Filling into prepared crust; chill until firm. Pour Coconut Pastry Cream over chocolate layer. Using an offset spatula, swirl Marshmallow Fluff onto tart. Use a kitchen torch to toast until lightly browned for about 30 seconds. Refrigerate for up to 2 days.