Clean and wash the porcini mushrooms, and if necessary wash them briefly. Cut large mushrooms smaller. Peel and dice shallots.
Heat the oil in a pan. Fry the mushrooms for 4-5 minutes. Add 1 tablespoon butter and shallots and continue to fry briefly. Season with salt and pepper.
In the meantime preheat the grill of the oven. Cut the mozzarella into small pieces. Wash the herbs, shake dry and pluck the leaves or needles from the stems. Mix with crème fraîche and milk. Place the mushrooms with the herb crème fraîche and buffalo mozzarella in one large or two small, greased casserole dishes.
Bake on the middle rack under the hot grill for 6-8 minutes. Baguette goes well with it.