1 1/2 tablespoons Stone-ground mustard
2 cloves Garlic, minced
1 1/2 tablespoons Cider vinegar
1/3 cup Pure maple syrup
1/3 cup Low-sodium chicken broth
2 teaspoons Chopped fresh thyme (divided)
1/4 teaspoon Salt
1 tablespoon Olive oil
4 - 6 ounces Boneless, skinless chicken breast halves
1/2 tablespoon Black pepper