The easiest side dish ever! These hobo dinners bring campfire cooking to your backyard. Grilled onions marinated in balsamic glaze, and cooked in a simple foil packet- quick, easy, and unbelievably delicious.
Fold a 36x18-inch piece of heavy foil in half to make an 18-inch square. Place onions in center of foil. Sprinkle with salt and pepper. Drizzle with balsamic vinegar. Bring up 2 opposite edges of foil; seal with a double fold. Fold remaining edges to completely enclose onions, leaving space for steam to build.
For a charcoal grill, place packet on the grill rack directly over medium coals for 25 to 30 minutes or until vegetables are tender, turning occasionally. (For a gas grill, preheat grill. Reduce heat to medium. Place packet on a grill rack over heat. Cover and grill as above.) Sprinkle onions with thyme before serving.