To make the crust, blend the flour and 1/4 teaspoon of salt in a food processor. Add in the butter and shortening and pulse until the mixture looks like coarse meal. Add the water and pulse until the dough begins to clump (you may need to add a bit more water by the teaspoon). Gather the dough into a ball and flatten it into a disk. Wrap in plastic and chill for at least 30 minutes.
Preheat the oven to 350 degrees. Roll out the dough on a floured surface to a 12 inch round. Transfer the dough to a 9 inch glass pie pan. Trim the overhang to 1 inch beyond the rim and crimp the edges. Chill the crust while you make the filling.
To make the filling: Use an electic mixer to beat pumpkin and brown sugar until well blended. Add eggs, lemon juice, cinnamon, ginger, nutmeg, 1/2 teaspoon vanilla extract, ground cloves, and 1/4 teaspoon salt and beat until blended. Add 8 ounces (1 cup) mascarpone cheese and beat until mixture is smooth. Pour filling into crust.
Bake pie until the filling is set, about 55 minutes. Transfer to a cooling rack and cool.
For the topping: Combine whipped cream, 1/4 cup mascarpone cheese, sugar, 1 teaspoon vanilla extract, and 1/8 teaspoon salt. Use an electric mixer and beat until the mixture forms soft peaks.