1. Preheat the oven to 350° degrees. Combine the graham cracker crumbs, sugar, butter, cinnamon, and salt in a medium bowl. Press into the bottom and up the sides of a 9-inch pie plate. Bake for 10 to 15 minutes, or until golden brown. Cool completely.
2. Line a rimmed baking sheet with foil. Spread marshmallows out into a single layer. Broil until the marshmallows are toasted.
3. Add the softened ice cream to the bowl of an electric mixer. (You can also do this by hand.) Mix on low until smooth. Add the marshmallows to the mixer and mix until swirled into the ice cream.
4. Pour the ice cream into the cooled crust and top with mini chocolate chips. Cover with plastic wrap and freeze until solid, at least 2 hours.
5. Serve slices with chocolate sauce if desired.
Homemade Chocolate Sauce
1. In a medium saucepan, whisk together sugar, cocoa, cornstarch, and salt. Add water and bring to a boil, stirring frequently. When the mixture begins to bubble, add butter and vanilla. Whisk until melted. Transfer to a container and keep leftovers in the fridge.