Stir milk, eggs and flour until smooth. Season with salt and nutmeg and let it swell for about 10 minutes. In the meantime clean and clean the mushrooms and cut them into approx. 5 mm thick slices. Bake about 8 pancakes one after the other in a coated pan (20 cm Ø) spread with oil.
Remove and put aside. Cut the bacon into fine cubes. Peel and finely dice onion. Leave the bacon in a hot pan, add the onion and sauté in it. Stir in crème fraîche and bring to the boil.
Add mushrooms and simmer for about 3 minutes. In the meantime grate cheese, add half of it to the mushrooms and stir in. Season with salt and pepper. Put the pancakes one after the other into an ovenproof casserole dish, fill with 2/3 of the mushroom ragout and fold up.
Pour the rest of the mushroom ragout and cheese over the pancakes and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for 10-15 minutes. Serve garnished with parsley.