01 - Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease it.
02 - In a small bowl, combine garlic powder, paprika, salt, and black pepper. Set aside.
03 - Pat the chicken breasts dry. Using a sharp knife, carefully cut a pocket into the side of each breast without slicing all the way through.
04 - Rub each chicken breast with olive oil. Evenly coat with the prepared seasoning mixture, ensuring to season inside the pockets as well.
05 - In a separate bowl, combine chopped broccoli, shredded cheddar cheese, cream cheese, Parmesan cheese, Dijon mustard, and minced garlic. Mix thoroughly.
06 - Carefully fill each chicken breast pocket with the broccoli-cheese mixture. Secure the openings with toothpicks, if needed.
07 - Place the stuffed chicken breasts onto the lined or prepared baking sheet.
08 - Bake for 25 to 30 minutes, or until the chicken is fully cooked through (internal temperature reaches 165°F/74°C) and the cheese filling is melted and bubbling.
09 - Allow the chicken to rest for 5 minutes. Remove toothpicks before serving.