Coat the moulds with melted butter and place them in the fridge.
Brush a second coat of butter, after the first coat has chilled, and dust a good spoonful of cocoa powder in each mould
In a bowl, melt the chocolate and butter together and leave to cool for about 10 minutes once completely melted.
In a second bowl, beat the eggs and yolks together with the sugar until thick and pale.
Sift the flour into the eggs and whisk.
Pour the melted chocolate into the egg mixture in thirds, beating each time.
Evenly divide the batter between the moulds.
Chill for at least 20 minutes.
Heat oven to 200C/gas 6.
Place the fondants on a baking tray, then bake for 10-12 minutes until the tops have formed a layer and they are starting to come away from the sides of their moulds.
Remove from the oven, then leave to sit for 1 minute before turning out.