Combine spinach, cream of mushroom soup, garlic and seasonings in a small bowl; spread evenly over noodles or other pasta in buttered 3 litre flat casserole. Distribute chopped sausage over the spinach mixture and sprinkle with chopped onion on top of sausage. Blend egg into ricotta and spread over all. Bake in a preheated 375-F oven 25 to 30 minutes or until golden, then allow to cool slightly. Top with garnish of tomato and parsley.