Boil the beans with 1/2 cup of salted water until crisp, place on a sieve and drain well. Finely chop the onion, sauté in clarified butter until translucent.
Add the minced meat and crushed garlic and fry until the meat has lost its red color, then season.
Put half of the beans in a greased gratin dish, spread the mince over it, cover with the rest of the beans. Mix the grated cheese and creme fraiche, season and spread over the beans. Baked in the oven at 225 ° for approx. 15 to 20 minutes until golden yellow.