Cheesy polenta offers a satisfying alternative to pasta and sauce on a weeknight. For a different flavor combination, substitute crumbled feta for mozzarella and fresh chopped mint for basil.
1. Preheat oven to 400°F. Place 4 16-inch lengths of foil on work surface. Fold foil in half from short side. Unfold. Shape corners and edges of one half into semicircular “bowl” with 1/2-inch sides. Coat insides of foil with cooking spray.
2. Place 4 polenta slices, slightly overlapping, in each foil semicircle. Arrange 4 tomato slices over polenta. Scatter 8 olive halves (if using) over tomatoes. Drizzle each serving with 1 tsp. garlic olive oil and 1/2 tsp. balsamic vinegar, and sprinkle with 1/4 tsp. Italian herbs; season with salt and pepper (if desired), and top with 1/4 cup mozzarella. Fold other half of foil over ingredients, and seal edges in overlapping folds until packets are sealed. Transfer to baking sheet, and bake 25 to 30 minutes.
3. Remove baking sheet from oven, and transfer packets to serving plates. Let each person open packet slowly and carefully—escaping air will be hot. Garnish with basil.