01 - Preheat oven to 400°F. Lightly grease a 9x13-inch baking dish with olive oil or nonstick spray.
02 - In a mixing bowl, whisk together the Dijon mustard, whole grain mustard, honey, olive oil, minced garlic, smoked paprika, salt, and black pepper until smooth and well combined.
03 - Arrange the chicken breasts in the prepared baking dish. Pour the honey mustard sauce evenly over each piece, turning to coat all sides thoroughly.
04 - Bake uncovered for 25–30 minutes, until the chicken reaches an internal temperature of 165°F and juices run clear when pierced with a fork.
05 - For a golden, caramelized finish, switch the oven to broil and cook for an additional 2–3 minutes, watching closely to prevent burning.
06 - Remove from the oven, sprinkle with chopped fresh parsley, and serve immediately while hot.