Preheat oven to 350°F/180°C. Place the pie crust in a 9-inch pie dish, crimp the edges, and brush with egg wash. Add a piece of parchment paper or foil, and fill with pie weights or dried beans. Bake for 8 minutes, then remove the weights and paper and bake for 5 more minutes. Remove the crust from the oven and let it cool on a wire rack.
In a large mixing bowl using a hand mixer on low speed, mix the pumpkin puree, dark brown sugar, cornstarch, spices, and salt.
Then add the heavy whipping cream and the eggs one at a time until just combined. Do not overmix the eggs as it will add too much air into the filling.
Pour the mixture into the crust and bake for 50-55 minutes until only the center of the pie is still a little jiggly when you lightly move the pan. If the pie crust browns too quickly, you can cover the edge with aluminum foil or pie shields once it reaches the desired color.
In a medium bowl, combine all of the ingredients for the pecan topping. Stir with a spatula until evenly combined and all the pecans are coated in the mixture.
Spoon the coated pecans evenly on top of the pie and lightly press the filling down so it adheres to the top of the pumpkin layer. Then return the pie to the oven and bake for 15 more minutes.
Remove the pie from the oven and cool on a wire rack for at least 2 hours. Transfer it to the refrigerator to finish cooling until ready to serve. Serve with whipped cream or vanilla ice cream.