Grease a 7-inch push pan with cooking spray and set aside.

Pour water into instant pot.

Combine graham cracker crumbs, light brown sugar, and 1/4 teaspoon pumpkin pie spice, and salt in a bowl and stir.

Slowly pour in melted butter and mix with a fork until the graham cracker mixture resembles wet sand.

Press graham cracker mixture into the bottom and 1/4 of the way up the sides of prepared push pan.

Place pan with crust in freezer while preparing pumpkin cheesecake filling.

Put cream cheese in a large bowl. Mix using an electric mixer for 2 minutes, until light and fluffy.

Add pumpkin, granulated sugar, sour cream, eggs and egg yolk, 1 tablespoon pumpkin pie spice, and vanilla to bowl.

Mix until fully combined.

Pour cheesecake batter into chilled pan with graham cracker crust.

Cover top of pan with a paper towel and then cover tightly with foil.

Carefully lower the pan onto a trivet in the instant pot either using the trivet or a foil sling.

Close lid and set pressure release valve to sealing.

Press manual or pressure cook button and set to 40 minutes.

Natural pressure release for 10 minutes and then quick release remaining pressure.

Carefully remove pan from instant pot.

Let cool at room temperature and then transfer to the fridge.

Chill at least 4 hours or overnight.

Serve topped with whipped cream, if desired.