Preheat oven to 350°F. Slice tops of tomatoes off, about 1/4 of the way down. Hollow out middle, removing all seeds. Add 1-2 heaping tbsp of marinara sauce into each tomato until it is close to reaching the brim. Add mozzarella on top.
Bake about 10 minutes on top oven shelf until cheese is melted and tomatoes are cooked but still firm. Turn heat to 375°F and bake an additional 5 minutes, until cheese begins to bubble and brown. Eat immediately.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.