In a medium bowl, stir together flour, sugar, and salt. Sprinkle butter over flour. With a pastry blender or clean fingerips, mix butter into flour mixture until ingredients look like cracker crumbs with lumps of butter the size of peas.
Sprinkle 3 tablespoons ice water over dough and stir with a fork. Squeeze a handful of dough with your hand; it should keep together and feel moist. Add additional water, as needed, until dough holds together and you can gather it up to form a ball. Work quickly and avoid overhandling.
Form dough into a flat disc. Wrap with plastic and refrigerate at least 1 hour.
Preheat oven to 400°F while you roll out pie dough.
On a lightly floured work surface, roll dough into a 12-inch circle. Carefully transfer to 9-inch pie plate. Crimp overhanging edges into a decorative border above the rim. Refrigerate while you prepare filling.
In a large bowl, whisk together sugars and spices. Add eggs, pumpkin, and half and half. Whisk well.
Place chilled pie plate on a baking sheet and pour in pumpkin filling. Bake until center is set but still wobbles slightly when you tap the side of the pie dish, 45 to 50 minutes. Transfer pie to a rack to cool. Filling will set as pie cools. Cool for at least 2 hours before serving, or refrigerate, covered, overnight.
Remove from refrigerator 45 minutes before serving. Serve with whipped cream.
