This is a recipe I have used often. The sauce pairs very well with chicken or pork (think tenderloin). It's better if you marinate the meat, but half the time I don't, and it's still fine.
For the sauce/marinade, mix together 4 teaspoons dried mustard, 1 teaspoon cinnamon, 1/4 cup of apple cider vinegar, 1 cup of maple syrup, 6 Tablespoons of dijon mustard and 1/4 cup of soy sauce. If you can marinate the meat overnight in the refrigerator, great. If not, try an hour at room temperature.
For these, I used split chicken breasts, removed them from the marinade and gave them a quick sprinkle of kosher salt and dotted them with butter.
I like butter.
Those went on a 400F gas grill, and I boiled the remaining marinade down to about half as much.
Take the chicken off the grill, slice, and serve with the reduced sauce.
If you'd like to marinate some chicken in mustard and maple in your own kitchen, here's the .pdf.