Summer Panzanella

Ingredients

• 2 (3/4-inch-thick) slices country bread
• 1 medium zucchini or summer squash, halved
• 1/2 large red onion, cut into 4 wedges
• 1/4 cup extra-virgin olive oil, plus more, to taste
• kosher salt, to taste
• freshly ground black pepper, to taste
• 1 clove garlic, minced
• 2 tablespoons red wine vinegar
• 4 cups mixed tomatoes, such as heirloom, vine-ripened, cherry, or grape, diced
• 1 cup fresh mozzarella, cubed
• 1/2 cup fresh basil leaves, packed, torn into bite-size pieces
• balsamic glaze, to taste, for serving