Fill a large sauté pan with boiling water. Tip in the macaroni and cook according to the pack instructions. (It may take slightly longer than suggested). Meanwhile, trim, wash and slice the leeks, quarter the mushrooms and roughly chop the tomatoes.
Drain the pasta and keep warm. Heat the oil in the pan. Add the leeks and mushrooms and fry for 4-6 mins until the leeks are tender. Toss in the tomatoes at the last minute. Season with salt if you want to and black pepper. Stir in the macaroni and let it warm through, then crumble the cheese over.
