Preheat the oven to 375°F (190°C).

Using a meat mallet, gently pound the chicken breasts to an even thickness.

In a bowl, combine the Brie cheese, diced apple, and chopped thyme.

Place a portion of the filling in the center of each chicken breast.

Fold the chicken over the filling and secure with toothpicks or kitchen twine.

In a skillet, heat a little oil over medium heat and sear the stuffed chicken for 3-4 minutes on each side until golden brown.

Transfer the chicken to a baking dish.

In a small bowl, whisk together the maple syrup, Dijon mustard, and apple cider vinegar.

Pour the glaze over the chicken in the baking dish.

Bake in the preheated oven for 20-25 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C).

Remove toothpicks or twine, slice the chicken, and drizzle with any remaining glaze before serving.