Method:

Melt the chocolate and butter together over a double boiler in your Instant Pot PRO. Cool slightly.
In a large mixing bowl, use a hand beater to beat together the eggs, egg yolks and sugar until pale and creamy. Pour in the cooled melted chocolate mixture and fold until combined. Add the flour and stir well. Share two-thirds of the mixture evenly into 4 x 1 cup well-greased ramekins. Spoon 2 tablespoons peanut butter into the centre of each mould and cover with the remaining chocolate mixture. Add 1 1/2 cup cold water into the inner pot of your Instant Pot PRO. Place the trivet inside and place the ramekins on top. Choose Pressure Cook at High Pressure for 8 minutes with 3 minutes rest. Then Quick Release the remaining pressure.
Carefully open the lid and remove the ramekins. Once they’re cool to touch, gently turn out the cakes, dust with cocoa powder and serve with ice cream.