Pulse the shortbread to fine crumbs in a food processor or beating with rolling pin in plastic bag. Add the melted butter and salt and pulse until the mixture has the texture of wet sand. Press into the bottom of a 6-7-inch springform pan.

In a stand mixer fitted with the paddle attachment, beat the cream cheese, mascarpone and sugar on medium-high speed until light and fluffy, about 3 minutes, scraping down the sides of the bowl occasionally with a rubber spatula. Add the vanilla and lemon zest; beat on medium speed until combined. Add the eggs, one at a time, beating after each addition until just combined. Scrape down the sides of the bowl and mix again. Remove the bowl from the mixer and fold in the chocolate chips.

Pour the batter into your springform pan. Cover the pan with a paper towel and then a piece of foil. Set aside.

Inside of your pressure cooker, add one cup of water and place trivet on top of the water. Gently lower the spring form pan on top of the trivet into the pressure cooker.

Put on the lid to the pressure cooker and set to “sealing”. Press Manual (High) for 36 minutes for 6 in spring form pan and 40 minutes for a 7 in spring form pan.

When the time is up, allow for the pressure cooker to come to a natural release for 10 minutes then vent so the remaining pressure is released.

Take the cheesecake from the pressure cooker and remove the foil and paper towel. Let cool for about 30 minutes.

Replace the paper towel and foil and put in refrigerator for at least 6-8 hours. Cut and enjoy!

For topping, microwave chocolate chips and heavy cream in bowl for 30 seconds to 1 minute. Stir until melted and drizzle over the top.