Cook the spaghetti al dente. Dice the bacon, fry in a pan, add the finely chopped onion and roast until golden. Add the ham cut into strips with the chopped tomatoes (without the juice from the can) and the mushrooms in the pan. Season everything with salt, pepper, basil and lemon juice and simmer for 10 minutes over low heat, add cream as required. Mix the sauce with the spaghetti and pour into an ovenproof dish. Sprinkle with chopped parsley and cheese and grill in the oven.