In a small bowl mix together your Dijon mustard, maple syrup, and red wine vinegar.
Place your chicken in a sprayed 9 by 13 pan. Pour your sauce on top of the chicken and sprinkle with dried Rosemary. Place it uncovered in your preheated oven. Let it bake for 20 minutes and then take them out and flip them over.
Cook for another 20 minutes or until your chicken is browned and cooked through.
Let the chicken cool for 5 minutes before serving. Spoon some extra sauce over the top when you put it on plates.