Step 1

Grease four ramekins with butter and set them aside.

Step 2

In a medium microwave-safe bowl, combine butter and chocolate chips and heat in 30-second intervals until melted. Make sure to stir well after each interval, as the residual heat will melt the chocolate.

Step 3

Add powdered sugar, eggs, egg yolks, and vanilla to the melted chocolate and whisk until smooth.

Step 4

Add cocoa powder, espresso, flour, and salt to the mixture and whisk until just combined.

Step 5

Fill ramekins halfway with batter, then add to each a heaping 1 tablespoon of peanut butter.

Step 6

Top with remaining batter, leaving about 1 inch for the cakes to expand.

Step 7

Cover ramekins tightly with foil.

Step 8

Place trivet inside Instant Pot and pour in the water.

Step 9

Arrange three ramekins onto the trivet and stack the fourth one in the center on top.

Step 10

Secure lid and seal the valve on old models, Pressure Cook/Manual on High for 20 minutes.

Step 11

After that, follow the manufacturer’s instructions to do a quick release.

Step 12

Carefully open the lid and using tongs remove ramekins from the Instant Pot.

Step 13

Uncover them and run a butter knife around the edges. After that, invert each ramekin onto a plate, then dust with powdered sugar before serving.