Stir together the brown sugar, pepper, salt, onion powder, and paprika in a bowl. Coat the pork chops with this mixture on both sides. Cover and place in the refrigerator 6 hours to overnight.
Place oven rack in it's highest position. Set oven to Broil.
Place pork chops onto a slotted, two-piece broiler pan. Stir together the maple syrup and spicy mustard. Broil pork chops for 5 minutes, then turn over, and broil for another 5 minutes. Brush the tops with the mustard glaze, and cook for 1 minute. Turn the chops over, brush again, and broil for an additional minute, or until cooked to your desired degree of doneness. Remove pork chops to serving plates and top with additional glaze, if desired.
