Preheat the oven to 350°. In a large bowl, mix 1/4 cup mustard with 1/4 cup honey, and olive oil. Add a pinch of salt and taste. Depending on what you like or based on your taste add more mustard, honey and salt. Spoon the sauce over the chicken and add the rosemary sprigs in a shallow casserole dish. Bake for about 45 minutes or when your chicken reads 175 degrees on a meat thermometer, drain off any excess chicken fat. Sprinkle with fresh ground pepper and serve.