Butter 4 small (150ml) pudding basins and dust with cocoa powder, shaking out the excess. Heat the oven to 180`c. Melt the butter and chocolate together in a bowl set over a pan of simmering water. Whisk the eggs, egg yolks and sugar together until pale and thick. Fold in the chocolate mixture, sift in the flour and cocoa and fold in with a large metal spoon or a spatula. Divide ½ of the mixture between the moulds, filling each one ½ full. Press a toffee into each pudding followed by a tsp of peanut butter. Next, cover the puddings with the remaining mixture so that they should be ¾ full. Place the puddings on a baking sheet and cook for 10 minutes. Leave to rest for half a minute before running a sharp knife around the edges and turning out onto serving plates. Dust with cocoa before serving immediately.