In a small bowl, combine the dusting ingredients, cocoa powder with plain flour; brush five small ramekins with melted butter and dust them with the cocoa mixture, tapping out the excess.
Over low heat, melt the butter and chocolate together, stirring occasionally. Let it cool slightly while beating together the sugar, salt and eggs. Using a rubber spatula, fold through the melted chocolate until no streaks remain then fold in the flour until it forms a thick dense paste. Preheat the oven to 220°C.
Spoon two-thirds of the batter into the prepared ramekins, then spoon the peanut butter mixture on top. Cover with the remaining chocolate batter. Bake when required, for 10 – 15 minutes until the tops are cracked; like a soufflé, it should rise slightly. Transfer to a rack and let cool for 5 minutes then serve immediately.
Tip: Ensure you don’t over-bake otherwise the centre will be dry and you won’t be able to enjoy a gooey lava explosion of chocolate and peanut butter!