Step 1: Prepare the Ramekins. Start by spraying the inside of each ramekin with cooking spray to prevent sticking. Then, sprinkle granulated sugar inside each ramekin, tilting them to coat the sides and bottom evenly.
Step 2: Melt the Chocolate and Butter. In a microwave-safe bowl, combine the chopped semi-sweet chocolate and unsalted butter. Heat in 30-second intervals, stirring in between, until melted and smooth.
Step 3: Mix the Batter. In a large mixing bowl, whisk together the eggs, egg yolks, and powdered sugar until well combined. Add in the melted chocolate mixture, a pinch of salt, vanilla extract, and flour. Gently fold the mixture until just combined.
Step 4: Fill the Ramekins. Divide the batter evenly among the prepared ramekins, filling each one about ¾ full.
Step 5: Set up the Instant Pot. Pour 1 cup of water into the bottom of the Instant Pot. Place a trivet inside and carefully arrange the filled ramekins on top.
Step 6: Cook the Lava Cakes. Close the Instant Pot lid and set it to cook on high pressure for 9 minutes. Allow for a 5-minute natural release before carefully venting any remaining steam.
Step 7: Serve and Enjoy! Once the pressure has been released, remove the ramekins from the Instant Pot using tongs and let them cool for about 1-2 minutes. Invert each ramekin onto a plate and serve immediately.