If you are using a frozen pie crust, you may need to partially bake it first. Check the back of the package for instructions. Most frozen crusts just require that you to sit it out on the counter for about 10 minutes before putting any filling into it. Put pie crust on a baking sheet. This will make it easier to lift it in & out of the oven.
If using a refrigerated pie crust, carefully unroll the pie crust and place into pie pan and crimp the edges.
Preheat oven to 425 degrees F.
Using an electric mixer, mix the melted butter, brown sugar, pumpkin puree together until combined.
Add in eggs, heavy cream, sour cream, spices, and vanilla.
Mix until thoroughly combined.
Pour batter into the pie shell, taking care not to overfill. Also, to keep pie edges from getting too dark, wrap edge of crust in aluminum foil.
Bake for 15 minutes at 425 degrees F, then reduce heat to 350 degrees F and bake for about 40-50 minutes.
Cool to room temperature for 2-3 hours (to allow the pie to finish setting up) then serve with whipped cream.