1/2 c. (1 stick) butter, cut into cubes, plus more for ramekins
1 c. chocolate chips
1/2 c. powdered sugar, plus more for topping
2 large eggs, plus 2 egg yolks
1 tsp. pure vanilla extract
1/4 c. unsweetened cocoa powder
1/4 c. all-purpose flour
1/2 tsp. kosher salt
4 tbsp. peanut butter
1 c. water
FOR THE INSTANT POT:
Step 1
Grease 4 ramekins with butter. In a medium microwave-safe bowl, combine butter and chocolate chips and melt in 30-second intervals until melted. Add powdered sugar, eggs, egg yolks, and vanilla and whisk until smooth. Add cocoa powder, flour, and salt and whisk until just combined.
Step 2
Pour ramekins only halfway with batter, then top each ramekin with about 1 heaping tablespoon of peanut butter. Top with remaining batter. Cover ramekins tightly with foil.
Step 3
Place trivet inside Instant Pot and pour in water. Place 3 ramekins on trivet and stack fourth one in center on top. Lock lid and Pressure Cook on High for 20 minutes.
Step 4
Follow manufacturer's instructions for quick release and, using tongs, carefully remove ramekins from Instant Pot. Uncover and run a knife or offset spatula around edges. Invert onto plate, then dust with powdered sugar before serving.
FOR THE AIR FRYER:
Step 1
Grease 4 ramekins with butter. In a medium microwave-safe bowl, combine butter and chocolate chips and melt in 30-second intervals until melted. Add powdered sugar, eggs, egg yolks, and vanilla and whisk until smooth. Add cocoa powder, flour, and salt and whisk until just combined.
Step 2
Pour ramekins only halfway with batter, then top each ramekin with about 1 heaping tablespoon of peanut butter. Top with remaining batter. Cover ramekins tightly with foil.
Step 3
Place ramekins in air fryer basket, working in batches if necessary. Cook at 375° for 12 minutes, remove foil, and cook for 6 minutes more.
Step 4
Carefully remove ramekins from air fryer; run a knife or offset spatula around edges. Invert onto plate, then dust with powdered sugar before serving.