Bring a large pan of water to boil and cook pasta for 12 minutes, or as instructed on packet. Drain well.
Meanwhile heat the oil in the large pan then add onion, bacon and mushrooms. Cook for 5 minutes, or until the onions have softened and bacon is cooked.
Add tomato soup or chopped tomatoes, tomato puree and seasoning. Stir well.
Add cooked pasta to sauce, stir to give a good coating.
Put the pasta and sauce into an ovenproof dish. Top with grated cheese.
Bake in a preheated 180 C / Gas 4 oven for 10 minutes, or till cheese has melted.