This works best with small- or medium-sized red or yellow onions. The amounts vary, but you’ll probably want an onion per person. Mix equal parts bourbon, brown sugar and soy sauce. Peel the onions, then cut them in quarters or sixths. Thread a skewer through the wedges to hold the slices together. Place in a Pyrex baking dish and pour the marinade over them. Let them sit, turning often, for up to 4 hours. Baste with the marinade while you grill them until they are cooked to the degree you desire.