01 - Preheat oven to 400°F. 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 chicken breasts dry. With a sharp knife, cut a deep pocket into each breast, without slicing all the way through.
04 - Rub olive oil and the prepared seasoning mixture evenly over each chicken breast, including inside the pockets.
05 - In a separate bowl, combine chopped broccoli, cheddar cheese, cream cheese, Parmesan cheese, Dijon mustard, and minced garlic until thoroughly mixed.
06 - Spoon the broccoli-cheese mixture into each chicken pocket, securing the openings with toothpicks if necessary.
07 - Place the stuffed chicken breasts on the prepared baking sheet, spaced apart.
08 - Bake for 25 to 30 minutes, until the chicken reaches an internal temperature of 165°F and the cheese filling is bubbling.
09 - Allow the chicken to rest for 5 minutes. Remove toothpicks before serving.