six 1/2-cup (4-ounce) pressure-safe ramekins, custard cups, or canning jars
a food processor
a pressure-safe rack or trivet
Instructions
Pour the water into the insert set in a 5-, 6-, or 8-quart Instant Pot. Put a pressure-safe rack or trivet in the insert.
Grease the insides of six 1/2-cup (4-ounce) pressure-safe ramekins, custard cups, or canning jars with cold butter, making sure it gets generously down into the joint between the side and the bottom of each.
Mix the graham cracker crumbs and melted butter in a small bowl until uniform. Divide this mixture among the prepared ramekins, about 1 1/2 tablespoons per container. Gently press to form an even bottom crust in each.
Put the cream cheese, sugar, egg, sour cream, flour, lemon zest, lemon juice, vanilla, and salt in a food processor. Cover and process until smooth, stopping the machine at least once to scrape down the inside of the canister. Divide this mixture evenly among the prepared ramekins, a generous 1/4 cup in each. Do not cover.
Stack the ramekins on the rack, placing three on the bottom level, then three on the top level with each sitting on a part of the rim of at least two below. Lock the lid onto the cooker.
Set the pot for Pressure Cook or Manual on High Pressure. The valve must be closed. Set the time for 15 minutes with the Keep Warm setting off.
When the pot has finished cooking, turn it off and let the pressure return to normal naturally, about 20 minutes. Unlatch the lid and open the cooker. Cool for 5 minutes.
Use hot pads or silicone baking mitts to transfer the (still hot!) ramekins to a nearby wire rack. Cool to room temperature, about 1 hour. Cover and refrigerate for at least 1 hour before serving — or up to 3 days.