Begin by preheating your oven to 375°F (190°C) to ensure it's hot when the chicken is ready to bake.
Prepare the chicken breasts by placing them between two sheets of plastic wrap or parchment paper. Gently pound the chicken with a meat mallet or rolling pin until they are about ½ inch thick.
In a small mixing bowl, combine the garlic powder, dried thyme, salt, and black pepper. Rub this spice blend evenly over both sides of each chicken breast.
On one half of each chicken breast, layer the sliced brie cheese, followed by a spoonful of cranberry sauce, and fresh spinach if desired.
Carefully fold the unstuffed half of each chicken breast over the fillings to create a pocket. Use toothpicks to hold them together if necessary.
In a large oven-proof skillet, warm the extra-virgin olive oil over medium-high heat. Add the stuffed chicken breasts and sear for about 3-4 minutes on each side until golden brown.
Transfer the skillet to the preheated oven and bake for approximately 20-25 minutes, or until the internal temperature reaches 165°F (75°C).
After baking, let the chicken rest for about 5 minutes before serving. Garnish with fresh parsley.
Notes
Pair with roasted vegetables or a light salad for a balanced meal.