Boil macaroni and steam brocolli. Mix together cheese (grated cheddar, mozarella and pamesan) with natural yogurt and couple of spoons of sour cream - season and stir in mustard. Stir cooked macaroni and quartered button mushrooms and salami pieces together with the cheese mixture. Top with sliced tomatoes and bake for 20 mins or so. Easy peasy lemon squeezy ... but hardly calorie free.