01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease the surface.
02 - In a small bowl, blend garlic powder, paprika, salt, and black pepper thoroughly. Set aside.
03 - Pat chicken breasts dry with paper towels. With a sharp knife, create a deep pocket in each breast without cutting all the way through.
04 - Rub olive oil over all sides of the chicken breasts, ensuring the interior of each pocket is coated. Evenly distribute the prepared seasoning mix inside and outside each pocket.
05 - Combine finely chopped broccoli, shredded cheddar cheese, softened cream cheese, grated Parmesan, Dijon mustard, and minced garlic in a mixing bowl. Mix until thoroughly blended.
06 - Generously fill each chicken breast pocket with the broccoli cheese mixture. Secure each opening with toothpicks if necessary to prevent filling from escaping during baking.
07 - Transfer stuffed chicken breasts to the prepared baking sheet. Bake for 25 to 30 minutes, or until the chicken is cooked through to an internal temperature of 165°F and the cheeses are melted and bubbling.
08 - Allow chicken to rest for 5 minutes out of the oven. Carefully remove toothpicks before serving.