Preheat oven to 350 degrees. Spray a 9-inch glass pie pan with baking spray.
Beat butter and sugar together until fluffy and combined. Add egg and vanilla until incorporated.
On low speed, add in flour, graham cracker crumbs, and baking powder. Divide the dough in half.
Press half of the dough into the bottom and sides of the prepared pie pan. Evenly spread the Marshmallow Creme over the bottom of the crust. Spread the broken chocolate pieces over the Marshmallow Creme.
Form the remaining dough into a ball and place it on a piece of wax or parchment paper. Top with another piece of wax or parchment paper and flatten into a 9-inch circle with a rolling pin. Carefully peel off the top piece of wax paper.
Flip the crust onto the top of the pie and peel off the other piece of paper. Pinch the dough together to form the crust. Bake for 20 minutes or until lightly browned. Cool completely and then slice and serve. When I serve mine, I heat the slices in the microwave for a few seconds and serve them with vanilla ice cream. Yum!