Cook pasta, adding 4 tsp of beef boullion to the water. Drain, but don't rinse.
~Meanwhile~ Saute italian sausage, drain if needed. Set aside.
If you're using fresh mushrooms, saute mushrooms, green pepper and onions in butter, garlic, pepper, and italian seasoning. (If you're using canned, just saute the onions, green pepper, and seasonings, then add the canned mushrooms at the very end of sauteing). Add the italian sausage back in.
Add soups, sour cream, and parmesan cheese, and milk. Mix well. Stir in cooked noodles and season to taste.
Pour into the prepared pan and top with mozzarella cheese. Cover.
Bake at 350 for an hour covered, then an additional 10 minutes, uncovered. Let set 5 minutes before serving.