Grilled Stuffed Tomatoes

6 medium-sized tomatoes
3 cups mozzarella cheese, shredded
3 Tbs. fresh basil, finely chopped
3 cups zucchini, chopped
4½ cups seasoned gluten free croutons, cut into ½-inch pieces
1 Tbs. olive oil
2 Tbs. apple cider vinegar
¼ Tbs. fresh ground pepper
Cut tomatoes in half crosswise and scoop out pulp, leaving ¼-inch shell. Chop pulp and drain. Drain tomato shells on paper towels while preparing stuffing. Stir mozzarella cheese, basil, zucchini, gluten free croutons, oil, vinegar and pepper in large bowl. Add tomato pulp and mix well. Divide mixture among tomato shells. Place filled tomato halves on grill on top of heavy-duty aluminum foil sprayed with cooking spray. Grill 20 minutes over medium-high heat or until tomatoes are hot and cheese has melted.