Cut the bacon into short strips and fry them crisply in a pan without fat. Take out and drain on kitchen paper.
Clean and wash the Brussels sprouts. Blanch in boiling salted water for 2-3 minutes. Drain, rinse with cold water and let drain. Halve the sprouts. Grease two ovenproof gratin dishes (each approx. 20 cm Ø) or a large flat casserole dish.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer).
Finely grate the cheese. Mix with crème fraîche and cream. Stir in half the bacon, season with pepper and nutmeg. Distribute into the moulds. Place the Brussels sprouts on top. Sprinkle the rest of the bacon on top and bake in a hot oven for 15-20 minutes until golden brown.