01 - Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease the surface.
02 - In a small bowl, combine garlic powder, paprika, salt, and black pepper. Set aside.
03 - Pat the chicken breasts dry with paper towels. Using a sharp knife, create a pocket in each breast, taking care not to cut all the way through.
04 - Rub each chicken breast with olive oil and the seasoning mixture, making sure to season inside the pockets as well.
05 - In a separate bowl, mix finely chopped broccoli florets, shredded cheddar cheese, softened cream cheese, grated Parmesan, Dijon mustard, and minced garlic until thoroughly combined.
06 - Fill each chicken breast pocket with the broccoli-cheese mixture, securing with toothpicks if necessary.
07 - Transfer the stuffed chicken breasts onto the prepared baking sheet.
08 - Bake for 25 to 30 minutes, until the chicken reaches an internal temperature of 165°F (74°C) and the cheese filling is bubbly.
09 - Allow the stuffed chicken to rest for 5 minutes before serving. Remove toothpicks prior to plating.