In a large bowl; mix onion, macaroni, cheese, water, salt, pepper & tomatoes. Pour into greased casserole dish. Cover & bake in preheated 350°F oven for 1 hour.
Meanwhile in a small skillet, melt butter over medium heat. Add bread crumbs and cook, stirring for 8 to 10 minutes or until crumbs are lightly toasted.
When casserole has baked for one hour, remove lid and sprinkle crumbs on top. Return to oven and place under broiler for 3 to 5 minutes or until browned.
Calories From Fat
% Daily Value*
Total Fat 0g
Saturated Fat 0g
Trans Fat 0g
Dietary Fibers 0g
* Percent Daily Values are based on a 2,000 calorie diet.
* Nutrition information is estimated based on the ingredients and cooking instructions as described in each recipe and is intended to be used for informational purposes only. Please note that nutrition details may vary based on methods of preparation, origin and freshness of ingredients used.