1. Wash zucchini and cut in half lengthwise. With a spoon, scoop out the seeds and chop. Transfer the zucchini shells to a baking sheet, lined with foil or parchment paper.
2. Preheat oven to 375 degrees F (190 degrees C).
3. In a bowl, mix together chopped zucchini flesh, sausage, bread crumbs, Parmesan and garlic.
4. Stuff each zucchini shell with the mixture and top with 2 tablespoons pasta sauce.
5. Cover with foil and bake in the preheated oven for approximately 40 minutes.
6. Remove foil, sprinkle with mozzarella cheese and bake for another 10 minutes, until the cheese is melted.