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 to create a seasoning mix.
03 - Pat chicken breasts dry with paper towels. Using a sharp knife, carefully slice a pocket in the side of each breast, ensuring not to cut all the way through.
04 - Rub each chicken breast with olive oil and generously apply the seasoning blend on all sides, including inside the pockets.
05 - In a medium mixing bowl, thoroughly mix chopped broccoli, shredded cheddar cheese, cream cheese, Parmesan cheese, Dijon mustard, and minced garlic until well incorporated.
06 - Fill each pocket with the broccoli-cheese mixture, distributing evenly. Secure openings with toothpicks if necessary to prevent filling from spilling.
07 - Place the stuffed chicken breasts on the prepared baking sheet, ensuring they are spaced apart for even cooking.
08 - Bake in the preheated oven for 25 to 30 minutes, or until the internal temperature of the thickest part of the chicken reaches 165°F (74°C) and the cheese filling is bubbly and golden.
09 - Allow the stuffed chicken breasts to rest for 5 minutes after baking. Remove and discard toothpicks before serving.