Start with the sauce. In a large frying pan, saute the ground beef in the olive oil until it loses its raw, red color, then remove and set aside. In the same pan, saute the sliced mushrooms and chopped onion in the butter until transparent. Return the beef to the frying pan, add all the other sauce ingredients, and cover. Simmer for 20 minutes.
Meanwhile, prepare the lasagne. Presoak your largest clay pot, top and bottom, in water for 15 minutes. Boil the lasagne according to directions on package, or as you would macaroni al dente, then drain and set aside.
Line the presoaked pot with a coating of olive oil, then add alternate layers of lasagne, sauce, mixed ricotta and Cheddar, and sour cream. When all these ingredients have been used up, sprinkle the top with the Parmesan cheese.
Cover the pot and place it in a cold oven.