Snap off the mushroom stalks and cut into small pieces. Peel and finely dice the onion and garlic.
Heat some oil in the pan and fry the onions, garlic and mushroom stalks in it. Add the cream cheese and sour cream. Chop the rosemary, basil and thyme or oregano (if fresh) and add them as well. Season with salt, pepper and chilli to taste.
Pour the finished cream into the mushrooms. Cut the leek and cook in oil and a little water for 5 minutes on a medium heat. Pour in a can of chopped tomatoes and season to taste. Add the drained corn and spread the sauce in a baking dish.
Place the stuffed mushrooms on top and cover with the mozzarella. Bake for 10 minutes in a preheated oven (150 ° C, top / bottom heat). Meanwhile, prepare the gnocchi in salted water according to the instructions on the packet and serve with the mushrooms.