Cream together butter and sugars. Add the eggs and beat well. Mix in peanut butter, heavy cream, and vanilla. Combine flour, baking powder, soda and salt together and add to creamed mixture.
Stir in most of the chocolate chips, reserving a few for the top.
Spoon mixture into a 2 ½ to 3 quart souffle dish or mold (sprayed with non-stick cooking sprathat will fit into your Instant Pot.
Place a small trivet (or fashion a little “ring” from aluminum foiin the Instant Pot, add 1 ½ cups of water, and then place the baking dish on the trivet.
Close lid and set valve to sealing. Set on a manual high pressure cooking time of 60 minutes.
Allow for a natural pressure release for 15 minutes and then let the rest of the pressure out if there is any remaining. Use hot pads and the trivet handles to lift the cake dish out of the pressure cooker and set on a wire rack to cool.
Once the cake has cooled, it should easily release onto a plate for serving