Start by preheating your oven to 430°F (220°C). Lightly grease a baking dish to prevent sticking and set it aside while you prepare the chicken and sauce. This ensures the chicken cooks evenly and doesn’t dry out.
Place the chicken breasts in the baking dish and drizzle with olive oil. Sprinkle oregano, basil, salt, pepper, and half of the minced garlic over the chicken. This step infuses the meat with a fragrant, balanced flavor before roasting.
Scatter halved grape tomatoes and sliced red onion around the chicken. These vegetables release natural sweetness and juices while baking, complementing the balsamic glaze perfectly.
In a small mixing bowl, whisk together balsamic vinegar, brown sugar, and remaining garlic. Pour this mixture evenly over the chicken and vegetables, ensuring every piece is coated for maximum flavor.
Bake the chicken for 20–25 minutes until fully cooked and juicy. Sprinkle shredded mozzarella over the top, then switch your oven to broil for 4–5 minutes until the cheese is golden and bubbly. Watch closely to avoid burning.
Finish with freshly chopped parsley or basil for a touch of color and freshness. Serve the chicken with rice, pasta, or bread to soak up the delicious pan juices. This dish makes for a complete, flavorful meal.