Preheat your oven to 375°F (190°C).
In a mixing bowl, combine chopped spinach, dried cranberries, Brie cheese, cream cheese, parsley, and garlic powder.
Using a sharp knife, create a pocket in each chicken breast by slicing horizontally without cutting all the way through.
Stuff each chicken breast with the prepared filling and secure with toothpicks if necessary.
Season the stuffed chicken breasts with salt and pepper on both sides.
Heat olive oil in an oven-safe skillet over medium-high heat. Sear the chicken breasts for 3-4 minutes on each side until golden brown.
Transfer the skillet to the preheated oven and bake for 20-25 minutes or until the chicken reaches an internal temperature of 165°F (75°C).
Let the chicken rest for 5-10 minutes before serving.