To make the pie crust: Add flour, salt, and shortening in food processor. Pulse once or twice. Add water, a little at a time, and pulse. Dough should be moist. Wrap dough in plastic wrap and refrigerate for about 30 minutes. When ready, roll dough to fit 9-inch pie dish.
To make the pumpkin puree: Cut pumpkin in half with a serrated knife, and clean out seeds and stringy insides. Slice each half into quarters. Place on a baking sheet and cook for about 20 minutes, or until pumpkin is tender. Cool, then remove pumpkin flesh from skin. Use a hand blender and puree the pumpkin until completely smooth.
To make the custard: Heat cream and milk in a small saucepan until mixture begins to bubble. Remove from heat and cool.
Combine the sugars, cinnamon, ginger, cloves, and salt in a small bowl. Beat eggs in a large mixing bowl until foamy. Beat in sugar and spice mixture until thick and smooth. Beat in pumpkin, then the cream mixture. The custard will be a very thin liquid.
Pour the pumpkin custard in pie shell and bake until the filling is set and the crust is golden brown, about 50-55 minutes. Remove from oven and cool. Refrigerate until chilled through.
To make the cream topping: Add 1-2 tablespoons sugar to 1 cup of heavy cream to a small mixing bowl. Beat on high speed until cream is thick. Dollop about a tablespoon on top of each slice of pie.
The recipe calls for a 1/2 teaspoon of allspice, but I do not use it.