Preheat oven to 350 degrees F.In a food processor, process graham crackers to make 1 1/2 cups.
Add sugar, salt and melted butter and pulse until mixed. Press into bottom and up sides of a 9 inch glass pie dish. Set on a cookie sheet and bake for 7 minutes.
Let cool completely.To make the filling, allow the ice cream to soften at room temperature. While it’s softening, combine the pumpkin, brown sugar and spices in a small saucepan.
Heat over medium just until mixture gets very hot (the point is to dissolve the brown sugar somewhat).
Let cool to room temperature.In a large bowl, stir together the softened ice cream and the pumpkin mixture.
Transfer to the cooled graham crust and put in the freezer for 3 hours or until solid.
Spread sweetened whipped cream over top and return to freezer for another hour or long enough to freeze the whipped cream.Before serving, allow pie to sit at room temperature for about 10 to 15 minutes to soften. I like to set it on a dishtowel soaked with hot water to help loosen the crust from the pie dish. While pie sits, drizzle with caramel sauce.