Mix the graham cracker crumbs, 1/4 cup of brown sugar, and melted butter in a bowl. Press the crust into a 9x9-inch square baking dish. Place the pumpkin into a large bowl, and mash it up with a spoon. Mix in 1/2 cup of brown sugar, salt, nutmeg, cloves, and 1 teaspoon of cinnamon until smooth. Gently stir in the softened ice cream. Spread the pumpkin mixture over the graham cracker crust. Freeze until firm, 4 to 6 hours; cut into squares.
Lightly mix the whipped cream with confectioners' sugar and a 1/4 teaspoon of cinnamon in a bowl; serve each square with a dollop of the sweetened whipped cream.
