Combine crushed gingersnaps, brown sugar, flour and cinnamon. Add melted butter. Using a fork, mix until dry ingredients are moist and will hold together. Press mixture into parchment-lined 7-inch springform or cheesecake pan. Set aside until cheesecake mixture is ready.

Lightly beat cream cheese to break up. Add eggs, sugar, rum extract, nutmeg, cinnamon, salt and cornstarch. Beat only until combined - don't over mix.

Scrap side of bowl.

Add eggnog. Mix only enough to make batter smooth. Don't over mix.

Pour eggnog mixture onto gingersnap crust.

Carefully tap pan with mixture in it onto counter or table to release any large air bubbles.

Place wire rack in bottom of Instant Pot. Add 1 cup cold water.

Using a tinfoil sling, carefully lower cheesecake into Instant Pot. Secure lid and set pressure release to close.

Cook cheesecake for 29 minutes using manual high pressure. When timer beeps turn Instant Pot off. Let cheesecake natural release (depressurize and cool without manually releasing pressure. This takes 10-20 minutes.

Once pressure has released, open lid carefully without dripping condensation from lid on cheesecake.

Gently dab top of cheesecake with a paper towel to remove liquid that may be on the surface.

Remove and set on wire rack to cool. Once it has cooled to room temperature, refrigerate for 2-4 hours. This will help it become firm.

Pipe sweet whipped cream on top and sprinkle with cinnamon.