Make The Crust
Position a rack in the center of the oven and preheat the oven to 350F degrees. Lightly grease the bottom and sides of a 9-inch springform pan. Cut an 18-inch square of heavy aluminum foil and wrap the foil around the outside of the pan.
Place the flour, sugar, salt, pecans, and ginger in the bowl of a food processor and process until the pecans are finely ground. Add the butter and process until the mixture forms coarse crumbs. Add the water and process until the dough starts to come together. Press the dough into an even layer over the bottom of the prepared pan.
Bake the crust for 23-25 minutes, until it is just beginning to brown. Place the pan on a wire rack and cool completely. Reduce oven temperature to 325F degrees.
Make The Filling
In a medium bowl, whisk together the pumpkin puree, heavy cream, vanilla extract, cinnamon, ginger, nutmeg and salt. Set aside.
In another medium bowl, beat the cream cheese at medium low speed until creamy, about 2 minutes, scraping down the sides of the bowl as necessary. Gradually add the sugars and beat until blended. Add the pumpkin mixture and mix again until blended. Add the cornstarch and mix just until combined. Add the eggs one at a time, mixing just to incorporate after each addition and scraping down the sides of the bowl as necessary. After all the eggs are incorporated, continue to beat the filling for an additional minute to ensure the mixture is smooth.
Scrape the batter over the cooled crust. Place the wrapped pan in a roasting pan or large baking pan. Pour enough hot water into the roasting pan to come up just 1 inch of the sides on the springform pan. Bake the cheesecake in the water bath for 65-75 minutes, until the center of the cake is set but still slightly wobbly (the cake will set completely as it cools).
Remove the cake pan from the water bath, place the pan on a wire rack, and carefully loosen the foil. Let the cake cool completely.
Refrigerate the cheesecake for at least 4 hours before serving, but 24-48 hours is ideal.
Make The Pumpkin Seeds
Position a rack in the center of the oven and preheat the oven to 325 degrees F. Lightly grease a baking sheet.
Place the pumpkin seeds in a small bowl. In another small bowl, whisk the egg white just until frothy. Add JUST ENOUGH of the egg white (approximately 1/2 tablespoon) to the pumpkin seeds to coat them. Add the salt, sugar and cinnamon and toss well to coat the seeds.
Spread the seeds in a single layer on the prepared baking sheet. Bake, tossing them occasionally with a metal spatula, for 15 to 20 minutes, until they begin to dry and change color. Place the pan on a wire rack and cool completely.
With your fingers, separate any clumps of seeds and store in an airtight container for up to a week.
Make The Whipped Cream
Add heavy cream, sugar and vanilla in a medium mixing bowl. Beat on high until desired whipped cream consistency is reached. Taste and add more sugar, if needed.
Remove the side of the pan and slice the cake with a thin-bladed sharp knife, wiping the knife clean between each cut. Garnish each slice with a dollop of whipped cream and a sprinkling of sugared pumpkin seeds.
Store any leftovers in the refrigerator, loosely covered, for up to 4 days.
For altitudes over 3,000 ft., note the following tips: When greasing the springform pan, grease heavily rather than lightly. Be sure to add the cornstarch step to help prevent cracking, and check your crust and cake at the lower end of the cooking time for doneness.