Melt the butter in a pot and remove from the heat. Mix flour and egg in a bowl. Gradually stir in milk and butter, season with salt and pepper. Grease a coated pan (approx. 20 cm Ø) with oil and heat up.
Put approx. 1/4 of the dough into the pan and bake while turning from both sides until golden brown. Also bake 3 more crepes, keep warm.
Clean, wash and dry mushrooms. Peel onion and cut into fine cubes. Heat 2 tablespoons of oil in a wide saucepan. Fry the onion in it. Add the mushrooms and fry for about 3 minutes. Add cream and simmer for 3-4 minutes.
Season with salt and pepper. Fry bacon in a pan without fat until crispy. Wash parsley, shake dry and pluck leaves from the stalks. Fill pancakes with mushroom ragout. Sprinkle with bacon, parsley and coarse pepper.