For 4 personns :
Heat the oven to 260°C.
Make melt the black chocolate with the butter in micro waves.
Whisk eggs with sugar and add the combination melted chocolate/butter.
Well mix before to include the flour into.
Grease muffins aluminium tins with butter (with after, a little coat of flour), and fill them to the tierce of the height and add the white chocolate's chunks into, cover with the rest of paste.
Fall the oven to 240°C and stuff into during 8 min.
Get out and then let it rest 2 minutes before to turn upside down on the dish.
Have a good delight !