Peel and wash the potatoes. Place them in a large pan filled with cold, salted water.
Bring to the boil and cook for 20 to 25 minutes.
When cooked, drain the potatoes.
Peel and finely chop the onions.
Heat the butter in a pan and sweat for 5 minutes until they are translucent.
Add the lardons and continue cooking for a few minutes.
Preheat the oven to 180°C. Butter a gratin dish.
Cut the potatoes and the Camembert into slices.
Place half the potatoes in the dish, and add half the onions and lardons.
Place half the camembert in the dish, and repeat the process with the remaining ingredients (potatoes, onions and lardons).
Pour the cream over. Add the remaining camembert. Season lightly with salt and pepper.
Put in the oven for 15 minutes until the cheese is nicely melted. Enjoy with a green salad.