Preheat your oven to 425°F and place the pie crust in a 9-inch pie pan, crimping the edges decoratively.
In a large mixing bowl, whisk together the pumpkin puree, sweetener, eggs, heavy cream, pumpkin pie spice, vanilla extract, and salt until completely smooth and well combined.
Pour the pumpkin filling into the prepared pie crust, smoothing the top with a spatula.
Bake at 425°F for 15 minutes, then reduce the oven temperature to 350°F without opening the door.
Continue baking for 40-45 minutes, or until the center is just set but still slightly jiggly (it will firm up as it cools).
If the crust edges start to brown too quickly, cover them with aluminum foil or a pie shield.
Remove from the oven and let cool completely on a wire rack, then refrigerate for at least 2 hours before serving.
Slice and serve with sugar-free whipped cream. Store covered in the refrigerator for up to 4 days.