Preheat the oven: Set your oven to 400°F (200°C).
Lightly oil a baking dish or line a sheet pan with parchment.
Prep the chicken: Pat the chicken dry with paper towels. Season both sides with salt, pepper, and Italian seasoning.
Optional sear for extra flavor: Heat olive oil in a skillet over medium-high heat. Sear chicken 2–3 minutes per side until lightly golden.
Transfer to the baking dish. If you skip searing, drizzle the oil over the chicken in the baking dish.
Add pesto: Spread about 2 tablespoons of pesto over each piece of chicken, coating the top evenly. If using garlic, sprinkle it around the chicken in the pan.
Tomatoes and cheese: Scatter the cherry tomatoes around the chicken.
Bake for 12–15 minutes, then remove the pan and top each chicken breast with mozzarella slices. Return to the oven.
Bake until done: Continue baking 5–10 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the cheese is melted and bubbly.
Finish and serve: Sprinkle with Parmesan and fresh basil if you like. Squeeze a little lemon over the top for brightness.
Serve hot with your favorite sides.