Slice onions in approximately 1/3 inch slices being careful to keep the slices together and not separate the rings. On a square of aluminum foil, place an onion slice, 1 heaping teaspoon of brown sugar and 1 small beef bouillion cube. (If your cubes are larger cut them in half or quarters.) Fold the foil up tightly over the onion slice making sure to seal all of the edges. Throw them on your hot grill for approximately 20 - 30 minutes. The foil will puff up like Jiffy Pop! They should be cooked all the way through and have a wonderful carmelized appearance. This recipe can also be done with smaller onions, just cut them in half, follow the same preparation and wrap them up like a Hersey's Kiss.