Prepare and prebake your pie crust according to your recipe.
Place gelatine powder in ¼ cup of cold water to soften. Or place a gelatine leaf in a bowl with ½-1 cup cold water to soften.
Prepare a double boiler. In the top of the bowl mix ½ cup brown sugar, cinnamon, ginger, and salt.
Mix in the pumpkin purée and cream.
Separate the eggs. Set the whites aside in the refrigerator for use later.
Add the three beaten egg yolks to the bowl.
Mix and cook, over the double boiler, for about 10 minutes. It will thicken over this time.
Remove from heat and add in the softened gelatine powder. If you are using the gelatine leaves make sure to squeeze out any extra water before adding it.
Stir to dissolve into the warm pumpkin mixture.
Chill for 1-2 hours.
When the pumpkin mixture is ready, beat the egg whites to soft peak.
While slowly beating, add in the last ¼ cup of brown sugar. Once incorporated, turn the mixer up and beat until the egg whites will hold a stiff peak.
Gently, fold the egg whites into the pumpkin mixture. Try to keep as much lightness from the egg whites as possible.
Pile this mixture into your prepared pie crust. Smooth it out and chill for an additional 2 hours.