Preheat your oven to 375°F (190°C).

In a large skillet, heat olive oil over medium heat. Sauté minced garlic for about 30 seconds, then add chopped spinach and cook for 3-4 minutes until wilted.

In a mixing bowl, combine wilted spinach, dried cranberries, goat cheese, cream cheese, salt, black pepper, and thyme. Mix well.

Butterfly each chicken breast carefully by slicing horizontally without cutting all the way through.

Season both inside and outside of the chicken breasts with salt and black pepper.

Fill each chicken breast with the spinach and cranberry filling, pressing gently to pack it in.

Secure each stuffed chicken breast with toothpicks or kitchen twine.

Place the stuffed chicken breasts in a greased baking dish, pour chicken broth around them.

Drizzle balsamic vinegar on top of the stuffed chicken breasts if using.

Cover the baking dish with foil and bake for 25 minutes. Remove the foil and bake for another 15-20 minutes until the chicken is fully cooked.

Remove from the oven and let rest for 5 minutes before serving. Remove toothpicks or twine before slicing.