Mix together the gluten-free graham cracker crumbs, melted butter, brown sugar, salt and cinnamon until completely mixed.
Press the crust mixture into the 9-inch pie tin. Bake the crust at 375F for 8-10 minutes. Set aside. Combine the pumpkin puree, heavy cream, eggs, softened butter, brown sugar, cornstarch, vanilla extract, cinnamon, ginger, nutmeg, cloves and salt in a bowl.
Whisk the filling ingredients together until smooth.
Pour the filling into the crust. Bake in the oven at 375F for 50-60 minutes, until the center hardly jiggles and a toothpick inserted into the center comes out mostly clean. The filling will firm up as it cools.
Cool the pie completely, about an hour, before topping with whipped cream and serving.