4 medium-sized Vidalia onions or other types of sweet onions
2 T balsamic vinegar
1/4 tsp. seasoned salt
1/4 tsp. dried thyme
1/4 cup olive oil
1-2 T freshly grated Parmesan cheese
ground black pepper to taste
Peel onions, cut in to slices about 1/2 inch (1.25 cm) thick, and separate into rings. Put onion rings into a large Ziploc bag.
In a small bowl, stir together balsamic vinegar, seasoned salt, and dried thyme. Whisk in olive oil. Pour marinade into plastic bag and let onions marinate in the refrigerator 4 hours or longer, turning a few times if you're home.
Preheat oven to 400 F/200 C. While oven preheats, drain onions in a colander placed in the sink. Spray non-stick baking sheet with olive oil or non-stick spray. Arrange onions on baking sheet, putting them in a single layer as much as you can.
Roast onions 30-40 minutes, turning about every 10 minutes. Onions are done when they are nicely browned, especially on the edges. Remove onions to serving dish, sprinkle with Parmesan cheese, season to taste with ground black pepper and serve hot.
Recipe adapted from one at Kayln's Kitchen