Please read my article Perfect Pressure Cooker Cheesecake Tips & Guide, before proceeding.
Add cookies and sugar to the bowl of food processor and pulse a couple of times, until small crumbs form. Melt butter in microwave or on stove top and add to graham cracker mixture. Pulse until just combined.
Pour cookie mixture into bottom of greased 6-inch cheesecake pan and press the mixture firmly into the bottom of the pan and no more than one inch up along the sides.
Place pan with crust into freezer for 20 minutes while you mix up the filling.
Blend together cream cheese, sugar, cream, flour, grated peels and vanilla extract until smooth.
Add eggs and yolk, one at a time, lightly mixing until just combined. Do not over mix the eggs.
Pour filling into the pan, on top of the crust.
Add 1.5 cups of water to the bottom of your pressure cooker and then place a trivet inside the pot.
Cover the cheesecake first with a paper towel and then with a piece of aluminum foil and loosely secure the foil.
Place cheesecake into pressure cooker using a sling.
Lock on lid and close Pressure Valve.
Cook at High Pressure for 37 minutes. Allow an 18 minute natural release.
After all pressure has been released, open pressure cooker and gently remove the pan. Remove the foil and paper towel. Tilt the cheesecake pan and dab off any liquid that may have accumulated.
The center will be slightly jiggly, but don't worry. The heat that is trapped inside will continue to cook the center while the cheesecake cools.
Whisk together the sour cream and sugar and then spread on the hot cheesecake.
Let cool on wire rack for at least one hour.
Lightly cover and place in refrigerator overnight.
Remove from pan and enjoy.