Step 1

For the cheesecake: Put the cookies and a pinch of salt in a food processor and pulse until the cookies are broken down into fine crumbs. Add the butter and pulse until completely combined. The texture will be similar to wet sand. Press firmly into the bottom and 1 inch up the sides of a 7-inch springform pan. Put the crust in the freezer while you make the filling.

Step 2

Wipe out the bowl of the food processor and add the cream cheese, pumpkin puree, vanilla, nutmeg, eggs, 3/4 cup of the sugar and 1 teaspoon of the cinnamon. Process until completely smooth, opening the lid and scraping down the sides of the bowl as needed. Pour the mixture over the crust.

Step 3

Tear off a piece of aluminum foil about 1 1/2 feet long and put the springform pan in the center. Wrap the foil around the pan, folding down the sides as needed so the top of the pan isn't covered. The aluminum foil should only be on the outside of the pan. Tear off a second piece of aluminum foil about 2 feet long and lay the foil in front of you with one of the longer sides closest to you. Folding it toward you (the long way), fold the foil in half once then fold once again to create a foil sling for the cheesecake.

Step 4

Pour 2 cups water in the bottom of a 6-quart Instant Pot® and insert the machine's trivet. Put the springform pan in the center of the foil sling, then pick up both sides of the sling, bringing them up the sides of the pan. Carefully lower the pan onto the trivet. Fold down the foil sling as needed so that it fits in the pot but does not touch the cheesecake. Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on high for 35 minutes.

Step 5

After the pressure-cook cycle is complete, turn off the heat and let the steam release naturally for 25 minutes. After 25 minutes, follow the manufacturer's guide for steam release and allow any residual steam to air out. Being careful of any remaining steam, unlock and remove the lid and carefully use the foil sling to lift out the pan and set it over a cooling rack. Remove the foil from around the pan, then use paper towels to blot off any excess liquid from the top and sides of the cheesecake. Use a small offset spatula or the tip of a paring knife to loosen the sides of the cheesecake from the pan. Allow to sit at room temperature until mostly cooled, about 1 hour. Cover with plastic wrap and refrigerate until completely set, at least 4 hours and up to overnight.

Step 6

Once fully chilled, remove the plastic wrap from the cheesecake and use a small offset spatula or the tip of a paring knife to again loosen the sides of the cheesecake from the pan. Remove the outer ring and set the cheesecake on a serving dish. Spread the whipped cream over the top. Whisk together the remaining 1/4 cup sugar and 1/2 teaspoon cinnamon in a small bowl. Dust the cinnamon sugar over the top of the cheesecake before slicing.