In a medium bowl, combine the flour and salt. Using a pastry blender, cut the shortening into the flour mixture until you get coarse crumbs. Sprinkle in the ice water, 1 Tbsp. at a time, combining lightly with a fork until the dough comes together, being careful to not overmix.
Divide the dough into halves and flatten each half into discs. Wrap in plastic and chill in the refrigerator for at least 30 minutes.
On a lightly-floured surface, roll one of the dough discs with a rolling pin into a 12-in. circle about 1/8-in. thick. (You can save the other disc in refrigerator for up to 10 days.)
Move the dough to a 9-in. pie plate and trim the edges, leaving about an extra inch hanging over the edge. Tuck the extra dough underneath itself to form a thick edge even with the rim that you can flute as desired.
For the pie filling:
Preheat the oven to 400°F/205°C.
Combine sugars, flour, salt, cinnamon, ginger and nutmeg in a large mixing bowl. Add the pumpkin puree, corn syrup and milk and mix well. Add the eggs and mix until smooth.
Pour into the pie shell and bake for 15 minutes at 400°F/205°C and then reduce the heat to 350°F/180°C and bake for an additional 45 minutes or until the edges of the filling are set but the center is still slightly loose. (If the edges get very dark, cover them with aluminum foil.) Cool on a wire rack and serve room temperature or slightly warm.