Onion Marmalade

4 medium red onions, halved and thinly sliced (1)
3 sprigs rosemary, leaves chopped (about 1 tablespoon) (1/4 t)
1/2 cup balsamic vinegar (2 T)
1/3 cup extra-virgin olive oil (1/4 C + 1 T)
3 tablespoons dark brown sugar (1T)
2 teaspoons kosher salt (1/2 t)
1/2 teaspoon freshly ground black pepper (1/8 t)
[measurements for one onion in ( )]
{1 T of fresh herbs = 1 t of dried}

On a large sheet of heavy-duty aluminum foil (or a doubled piece of regular), toss the onions with the rest of the marmalade ingredients.

Bring edges of foil up and crimp closed. Place package on the edge of the grill (over medium-high heat). Cook, turning the sealed package every now and then so the onions cook evenly until meltingly tender, about 45 minutes. (I used a stovetop grill)

(from Food Network)