Line a 6 or 7" springform pan with parchment paper.

In a stand mixer, combine the softened cream cheese, low carb granular sweetener, coconut flour and vanilla extract until smooth. Slowly add two eggs and an egg yolk. Finally, add the key lime juice and blend again.

Pour everything into the prepared pan, cover it with a paper towel, and wrap it in foil. Place a steam rack inside the Instant Pot together with some 1½ cups water, then put the springform pan onto the rack.

Lock the lid down, and seal it. Cook it on Pressure Cook (high) for 44 minutes. When the cooking time is complete, let the pressure release naturally.

Carefully remove the pan from the Instant Pot, and remove the paper towel. When the pan was cool, recover it in foil and let it set in the fridge overnight.

The next day, carefully removed the sides of the springform pan and the paper at the sides. For the topping, beat some heavy cream and sweetener until stiff, then smooth it over the pie.

To finish, add some finely grated lime zest.