Preheat oven to 400℉. Prepare shallow baking dish by spraying with nonstick cooking spray.
Slice top off tomatoes. Scoop out excess pulp and seeds. Place upside down on paper towels to drain any remaining liquid while you prepare stuffing.
In a large bowl, combine couscous, mozzarella, basil, Parmesan, garlic powder, salt and pepper.
Fill each tomato with stuffing mixture, pressing firmly. Place stuffed tomatoes in prepared baking dish.
Bake at 400ºF for 25 minutes or until tomatoes are tender and cheese is melted. Serve immediately drizzled with balsamic glaze and more fresh basil, if desired.
Notes
Substitute cooked quinoa for the couscous to make this dish gluten-free.
Not crazy about fresh mozzarella? Try regular shredded mozzarella or another type of cheese.
Stuffed tomatoes can be completely prepared ahead of time, up to a day in advance, and refrigerated until ready to bake. Add about ten minutes to the baking time.