Preheat oven to 175C
Wash tomatoes and cut the tops off at about 1.5 cm below the top of the tomato.
Scoop out the insides and place in a bowl. Be careful not to scoop too close to the skin or it may split when cooking.
Add the rice, onion ¾ of the cheese, pasta sauce and mushroom into the bowl with tomato flesh.
Mix together and place back into the tomato shells.
Place in an oven proof dish and sprinkle with remainder cheese.
Add a little water to the bottom of the dish and bake 25 minutes or until the cheese is nicely melted and brown and the tomatoes have softened.
You could also added shredded basil leaves for extra flavor.Step 2