2cupsgingersnap cookiescrumbled, about 5 ounces (once ground it will give you a little over a cup)
For the Filling
1tablespoonlight corn syrup
¼teaspooncream of tartar
1teaspoonpure vanilla extract
For the Sauce
1tablespoonbourbon or dark rumoptional, or use 1 teaspoon vanilla
Make the crust. Preheat the oven to 325. In a food processor, grind the gingersnap cookies until fine crumbs. Next brown the butter by placing it in a small saucepan and cooking it over medium high heat until the milk solids just begin to turn brown (see my Know How section for more details on browning butter). Remove from the heat and pour into the gingersnap crumbs. Pulse until moistened, then pour into a deep pie plate, pressing evenly on the bottom and up the sides. Bake for 8-10 minutes, then let cool completely.
Place the pumpkin puree in a medium bowl, add the spices and honey and mix well with a whisk. Set aside.
Prepare a double boiler by setting a pot of simmering water on the stove. Have ready a large, heat-proof bowl that can sit on top of the pot, and be sure that it is not resting in the water. It should hover just above it. Place the egg whites, water, corn syrup, cream of tartar, sugar, and vanilla in the bowl. Beat over simmering water for 4 minutes, whisking constantly.
Remove the bowl from the heat and using hand held electric beaters, beat the egg whites for 5 more minutes until they are fluffy white, thick, and cooled off. (You can also transfer the mixture to a kitchenaid and beat for 5 minutes in the stand mixer).
In a separate bowl, whisk the heavy cream until you have whipped cream.
Add the pumpkin to the egg whites and mix to combine. Next fold in the whipped cream using a rubber spatula. Scrape the filling into the cooled pie crust, smooth the top, then place in the freezer. Freeze for at least 6 hours, and up 2 days.
Make the sauce while the pie chills. In a small saucepan, combine the butter, sugar, and ¼ cup of the cream. Bring to a simmer over low heat, stirring until the butter is melted and the sugar is dissolved and it is smooth. Let it cook for 3-4 minutes at a low simmer without stirring, then remove from the heat. Stir in the bourbon or vanilla. The sauce will keep in the refrigerator for two weeks. Reheat in the microwave or stovetop, stirring, before using.
To serve, cut a slice of the pie and drizzle it with the butterscotch sauce, or a store bought caramel if you prefer.