Preheat oven to 400°F (200°C). Pat chicken breasts dry. Using a sharp knife, cut a deep horizontal pocket into the thickest side of each breast, being careful not to cut through. Season inside and out with salt, pepper, and Italian seasoning.

In a bowl, combine mozzarella, halved tomatoes, sliced basil, and minced garlic. Drizzle with 1 tsp olive oil and a pinch of salt. Toss gently.

Spoon the Caprese mixture evenly into the pocket of each chicken breast. Do not overstuff. Secure opening with toothpicks if necessary.

Heat 1 tbsp olive oil in a large oven-safe skillet over medium-high heat. Once hot, add the stuffed chicken. Sear without moving for 3-4 minutes until a deep golden crust forms.

Carefully flip the chicken breasts. Immediately transfer the skillet to the preheated oven.

Bake for 15-20 minutes, or until the internal temperature reaches 165°F (74°C) when measured with a meat thermometer.

While chicken bakes, make the glaze: In a small saucepan, combine balsamic vinegar and honey. Simmer over medium heat, then reduce to low and cook for 8-10 minutes until reduced by half and syrupy. Set aside.

Remove skillet from oven (handle will be hot!). Transfer chicken to a cutting board and let rest for 5-10 minutes. Drizzle with balsamic glaze, garnish with fresh basil, and serve.