Preheat oven to 400°F/200°C.

Spray four, 5 ounce ramekins with non-stick spray. Dust with cocoa powder and tap over the sink to discard any excess. Place them on a baking sheet and set aside.

Fill a pan with water and heat until low simmer. Set a heatproof bowl on top of the pan (make sure bowl does not touch water). Add the butter, peanut oil and chocolate to the bowl and stir until melted, turn off the heat.

To a mixing bowl or stand mixer add the eggs, egg yolks and sugar. Beat on low speed for 1 minute then faster speed for 2 minutes until pale and fluffy.

Pour the melted butter and chocolate slowly into the egg mix while whisking. Add the flour and in small batches, whisking in-between additions, until well combined. Whisk in the espresso powder until blended.

Fill a ramekin 1/3 full of chocolate mix, add a tablespoon of peanut butter on top, then cover with more chocolate mix. Repeat with all ramekins.

Place all the ramekins onto a baking sheet and bake in the center of the oven for 10 minutes until the edges look cooked and the centers are sunken and look moist. Remove from oven and allow to cool for 10 minutes in the ramekins.

To remove from the mold, run a knife around the edge and turn onto a serving plate. Serve immediately with chopped peanuts.