For the Crust
- 1/2 cup (1 stick) melted unsalted butter, plus more, unmelted, for pan
- 1 3/4 cups graham cracker crumbs
- 1/4 cup sugar
For the Cheesecake
- 1 (8-ounce) package cream cheese, room temperature
- 2 large eggs
- 3/4 cup sugar
For the Pumpkin Mousse
- 1 (1/4-ounce) envelope gelatin
- 1 (15-ounce) can pumpkin puree
- 3 large egg yolks
- 3/4 cup sugar
- 1/2 cup milk
- 1/2 teaspoon coarse salt
- 2 teaspoons ground cinnamon
- 3 large egg whites
For the Whipped Cream Topping
- 1 cup very cold heavy cream
- 1 tablespoon sugar
- 1 teaspoon pure vanilla extract
- Make the crust: Preheat oven to 350 degrees. Butter a 9-by-13-inch baking dish; set aside.
- In a large bowl, combine melted butter, graham cracker crumbs, and sugar; stir until well combined. Press graham cracker mixture into bottom of prepared baking dish in an even layer; set aside.
- Make the cheesecake: In the bowl of an electric mixer fitted with the whisk attachment, whisk together cream cheese, eggs, and sugar until fluffy. Spread cheesecake mixture over crust in baking dish. Transfer to oven and bake for 20 minutes. Remove from oven and let cool.
- Make the mousse: Fill a small bowl or liquid measuring cup with 1/4 cup water; sprinkle gelatin over top and let soften. In a large heatproof bowl, mix together pumpkin, egg yolks, 1/2 cup sugar, milk, salt, and cinnamon. Set bowl over (but not touching) simmering water; whisk pumpkin mixture until thickened, 8 to 10 minutes. Remove bowl from heat and whisk in gelatin mixture. Let cool to room temperature.
- In the clean bowl of an electric mixer fitted with the whisk attachment, beat egg whites until soft peaks form. Add remaining 1/4 cup sugar and continue whisking until medium peaks form. Fold into cooled pumpkin mixture. Spread pumpkin mixture over cheesecake; Cover and transfer to refrigerator until set, at least 8 hours and up to overnight.
- Make the whipped cream: In the bowl of an electric mixer fitted with the whisk attachment, whisk together heavy cream, sugar, and vanilla until soft peaks form. Spread over cake or serve cheesecake with a dollop on the side.
Note: Raw eggs should not be used in food prepared for pregnant women, babies, young children, or anyone whose health is compromised.