Prepare the Crust: In a small bowl, mix together the graham cracker crumbs, brown sugar, and melted butter until well combined. Press this mixture firmly into the bottom and about an inch up the sides of a 7-inch springform cheesecake pan. (For an extra crisp crust, you can optionally bake it at 325°F for 12-15 minutes, but it's not essential for this quick recipe!)
Whip the Creamy Filling: In a large mixing bowl, use an electric mixer to beat the softened cream cheese on low speed until perfectly smooth. Gradually add the granulated sugar, beating until just combined. Stir in the sour cream, vanilla extract, fresh lemon juice, and lemon zest until everything is smooth. Finally, gently mix in the eggs one at a time, beating just until they are incorporated – be careful not to overmix!
Pressure Cook Your Cheesecake: Pour 1 cup of water into the bottom of your Instant Pot liner. Carefully place the cheesecake pan with the filling onto the trivet inside the Instant Pot. Secure the lid and make sure the venting knob is set to the sealed position. Cook on high pressure for 22 minutes.
Cool & Chill for Perfection: Once the cooking cycle is complete, allow the pressure to release naturally. Once the float valve drops, carefully open the lid. Use the edge of a paper towel to gently blot any condensation from the top of the cheesecake. Let the cheesecake cool on the counter at room temperature for at least an hour. Then, transfer it to the refrigerator to chill for a minimum of 4-6 hours (or ideally overnight) for the best texture.
Serve & Enjoy: Once thoroughly chilled, remove the cheesecake from the springform pan. Serve this cool, creamy, and wonderfully zesty treat as is, or with a dollop of whipped cream and a slice of lemon for garnish!