You will need
Use some of the butter to grease 2 150ml souffle dishes or ramekins
Put the chocolate, 4 tbsp milk and the sugar in a small saucepan. heat gently, stirring, until the chocolate is completely melted and the sugar dissolved.
Blend the remaining 1 tbsp milk with the flour in a small basin to make a smooth patse. Stir into the chocolate mixture.
Pour the mixture into the saucepan and bring to the boil. Cook for 2 minutes, stirring all the time. Stir the remaining butter in a little at a time, then remove the saucepan from the heat and leave the mixture to cool until lukewarm.
Beat in the egg yolk. Whisk the egg white until stiff and fold carefully into the chocolate mixture until evenly blended.
Turn the mixture into the dishes and bake in the oven at 200X/400F/Gas Mark 6 for about 15 minutes until well risen and firm to the touch. Serve immediatly.
cooking for one or two