Preheat the oven to 375°F (190°C).
Using a sharp chef's knife, cut a horizontal pocket into the thickest part of each chicken breast, ensuring you do not cut through the opposite side.
Season the interior and exterior of the chicken breasts with salt, black pepper, and dried thyme.
Stuff each pocket with 1 ounce of Brie cheese and 2 tablespoons of cranberry sauce; secure the openings with wooden toothpicks.
Heat olive oil in a large oven-safe skillet over medium-high heat.
Sear the chicken for 3-4 minutes per side until a golden-brown crust forms.
Add the minced garlic and chicken broth to the skillet to deglaze the pan.
Transfer the skillet to the preheated oven and roast for 12-15 minutes, or until the internal temperature reaches 165°F (74°C).
Remove from the oven and allow the chicken to rest for 5 minutes before removing toothpicks and serving.