Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius).
Using a sharp chef knife, cut a horizontal pocket into the thickest part of each chicken breast, ensuring the blade does not pierce through the opposite side.
Stuff each pocket with approximately 1 ounce of brie cheese and 2 tablespoons of dried cranberries. Secure the edges with wooden toothpicks.
In a small ramekin, combine the rosemary, garlic powder, salt, and pepper. Season both sides of the chicken breasts evenly with the spice blend.
Heat olive oil in a large oven-safe skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 3 to 4 minutes per side until a golden-brown crust forms.
Transfer the skillet directly into the preheated oven and bake for 12 to 15 minutes, or until the internal temperature reaches 165 degrees Fahrenheit (74 degrees Celsius).
Remove from the oven and allow the chicken to rest for 5 minutes before removing the toothpicks and serving.