Chocolate soufflé

Preheat oven to 200°C/400°F/gas 6. Brush 4 ramekins with butter. Chop chocolate, and melt on very low heat in a saucepan. Stir until smooth and keep warm. Scald milk in a medium saucepan. In a large bowl, beat yolks and 4 tablespoons sugar until pale and fluffy, using an electric mixer. Beat in flour until well combined. Slowly add half of the hot milk and keep mixing. Add mixture to saucepan withremaining milk. Bring to a boil over medium-high heat, stirring constantly. Simmer for 2 to 3 minutes more and whisk in the melted chocolate. In a large bowl, beat egg white sand cream of tartar until soft peaks form.Gradually add remaining 2 tablespoons sugar. Beat until stiff. Spoon 1/4 of the whites into chocolate base, and whisk thoroughly until smooth. Quickly foldremaining whites into mixture untilcombined. Transfer to the ramekins. Bake for 15 minutes at 200°C. Reduce heat to 180°C/350°F/gas 4 and bake 10 minutes more. Serve immediately!