Combine all crust ingredients in a blender and blend until mixture becomes the consistency of damp sand.
Pour crust ingredients into a 7 inch springform pan. Be sure to pat down the crust using a spatula or spoonula. The crust should cover the entire bottom of the pan and about an inch of the side of the pan.
Make the cheesecake filling
Clean out your blender. You’re going to use it again. :)
Combine all cream cheese, sugar, vanilla and eggs in a blender and blend just until fully combined. Do not over mix. The more you mix the cheesecake filling, the more air that will get added. The more air, the fluffier the cheesecake will be. I was looking for a denser cheesecake so I made sure to only blend until combined.
Add in ¼ chocolate chips and ¼ mini marshmallows. Blend for 3-5 seconds. This should be a very quick blend just long enough to break up the chocolate chips and marshmallows.
Pour all of the cheesecake mixture into springform pan on top of crust. Pan should be about ¾ of the way full.
Tap the filled pan several times on the counter to eliminate all of the extra air. Cover entire pan with aluminum foil. Be sure to cover the bottom and sides too.
Bake the cheesecake
Place trivet into pressure cooker along with 2 cups of water.
Place springform pan into your sling. I use the OXO Good Grips Sling and it works perfectly. If you don’t have a sling, you can make one by folding strips of foil and cradling your pan in and out of the Instant Pot.
Gently place sling into Instant Pot onto trivet. Close Instant Pot lid and cook on high pressure for 45 minutes. Once timer beeps, let pressure natural release for 25 minutes. Release remaining steam and open lid.
Gently remove sling and cheesecake from pressure cooker. Remove the foil. The center of the cheesecake will have a jiggly spot about the size of a half dollar. If more of the center is jiggly, pressure cook for an additional 5 minutes. If the cheesecake has blossomed, gently tap on counter top several times to remove additional air.
Using a knife, gently separate cheesecake from sides of pan. You just want to make sure that it doesn’t stick once it’s cooled.
Cool on counter for about an hour and then place in refrigerator. Cool cheesecake for at least 2 hours.
Remove cheesecake from pan.
Decorate the cheesecake
Depending on what type of chocolate sauce you are using, you may need to melt it to make it easy to pour. If needed, melt chocolate sauce until it is a pour-able consistency. Pour ½ of the chocolate sauce on the top of the cheesecake, it’s ok if it drips over the side a little bit.
Evenly top the cheesecake with marshmallow fluff. I put it in a piping bag and piped the frosting in a swirl design on the top but you can spread it on with a knife or spatula if desired.
Sprinkle mini marshmallows, chocolate chips and crushed graham crackers on the top and then drizzle with remaining chocolate sauce.