Spray a 6” springform pan with non-stick spray, setting it aside.

In a small bowl combine the graham cracker crumbs and melted butter; mix well. then press this mixture firmly into the bottom of the sprayed springform pan; reserve.

Using an electric mixer, beat together: softened cream cheese, flour, sugar, vanilla and lime zest, scraping sides and bottom of bowl to ensure all ingredients are mixed together well.

Add eggs one at a time and then egg yolk; beat until just combined.

Mix in key lime juice and whipping cream, besting until just combined; pour over prepared crust in spring form pan.

Gently tap pan on countertop a few times to remove any large air bubbles that may be in filling.

Add 1 ½ cups water to the Instant Pot, then place trivet into the bottom of pot.

Place a dry paper towel over the top of the filling in the springform pan, then place a sheet of aluminum foil on top of paper towel, tightly wrapping the pan with aluminum foil.

Using a foil sling, lower the wrapped cheesecake pan into the Instant Pot.

Lock the lid into place, choosing the high pressure setting for 37 minutes.

When the timer sounds, use a natural pressure release for 18 minutes, then a quick release to remove any remaining pressure from the Instant Pot.

Using the foil sling, carefully lift the cheesecake from Instant Pot to a wire cooling rack; carefully remove the foil and paper towel, then carefully run a sharp paring knife around the outside edge of the cheesecake, gently loosening it from the sides of the pan.

Let the cheesecake cool for 30 minutes, then release and remove the outer ring of the springform pan that encases the cheesecake.

Cover the cheesecake and refrigerate 6-8 hours, or overnight, until very chilled.

In a mixing bowl, using an electric mixer, beat the whipping cream and sugar until stiff; gently fold in the zest of ½ of a lime.

Place the prepared whipped cream mixture into a piping bag fitted with a large star tip.

Pipe the whipped topping onto the top of cheesecake as desired, in a decorative pattern.

Zest the remaining half of lime over the top of the whipped cream and the center of the cheesecake.

Place the lime slice halves around perimeter of cheesecake by sliding them gently into whipped cream, as desired.

Refrigerate cheesecake (covered) until ready to serve.