Break chocolate into small pieces and place in a steel bowl with the butter. Place the bowl over a saucepan of boiling water on the cooktop, making sure the water does not touch the bottom of the bowl. Heat until both the chocolate and the butter have melted. Once all melted, stir to combine the chocolate and butter and set aside to cool slightly.
Break the eggs into another bowl then add the sugar and flour and whisk until combined. Gently stir the through the chocolate and butter mixture.
Brush the inside of four 1 cup capacity ramekins or small heat proof bowls with melted butter.
Pour the mixture into the ramekins dividing amongst them evenly.
Place into the centre of the oven and cook for 20 mins until the top of the mixture is cooked and may be cracked.
Allow to cool slightly and then dust with icing sugar and serve. The inside will be HOT.