Boil potatoes with skin in boiling water for about 25 minutes. Then allow to cool slightly. Hollow out the potatoes to a rim of about 1 cm. Mash the hollowed out potatoes with a fork. Heat the butter. Sauté the leek and garlic for about 5 minutes. Mix with the mashed inside of the potatoes, half of the grated cheese, crème fraiche and marjoram.
Season as needed and then stuff the mixture into the potatoes. Place them in greased gratin dishes. Sprinkle each potato with the remaining cheese, pour the beer evenly over the potatoes and cover the molds with aluminum foil.
Put the molds in the oven. Bake in the preheated oven at 200°C on the middle shelf for about 10 minutes. Then remove the aluminum foil and bake for 15 minutes. Serve hot.
Tip: Serve with rice.