Honey Mustard and Red Onion Barbecued Chicken

2 tablespoons vegetable oil
1/2 red onion, chopped
1/4 cup apple cider vinegar
1/4 cup brown sugar, a couple of handfuls
1 cup chicken stock
1/2 cup prepared honey mustard (recommended: Honey Cup brand)
1/2 teaspoon allspice, eyeball it
1/2 teaspoon curry powder, eyeball it
4 pieces boneless, skinless chicken breast
4 boneless, skinless chicken thighs
Vegetable oil, for drizzling
Salt and freshly ground black pepper

Preheat grill pan or griddle over medium high heat. Pour 2 tablespoons vegetable oil into a small saucepan over moderate heat. Add red onions and saute 3 to 5 minutes. Add vinegar and reduce by half, 1 to 2 minutes. Add brown sugar and cook 1 minute to incorporate. Whisk in broth and honey mustard, allspice and curry. Bring sauce to a bubble.

To Freeze: Freeze in freezer safe container.

To Reheat: Coat chicken with a drizzle of oil and salt and pepper, to your taste. Place chicken on hot grill and cook 4 or 5 minutes, then turn. Baste chicken liberally with sauce and cook another 5 minutes. Turn once again and baste. Cook 2 or 3 minutes more to cook through and transfer chicken to a platter and serve.