Remove the less beautiful leaves from the Brussels sprouts and cut them in half.
Cook them for 4 minutes in boiling water, drain, rinse for 30 seconds with cold water and let them drain well, if necessary, shake them through a clean towel.
Put them in a baking dish.
Mix the cream with the sixth, herb greedily with pepper from the mill, salt and muscate nut and a half of the finely chopped rosemary, pour over the Brussels sprouts, mix again.
Mix panko, cheese and rosemary and sprinkle over the Brussels sprouts.
Let it gratinate nicely for 25 to 30 minutes at 185 °.