Another courtesy of Moosewood Restaurant New Classics
Roasted Caramelized Balsamic Onions
2 large sweet onions (our vidalia-type work great!)
1/4 c unsalted butter
1/3 c balsamic vinegar
1/4 tsp thyme
1/4 tsp salt
ground black pepper to taste
Preheat the oven to 450 degrees F. Cut the onions into halves across the equator. Remove the papery skin and any tough outer layers. Take care not to score the onion layers when peeling down. Do not cut off the root or stem ends. Place the onion halves cut side down in a 9 inch square baking pan.
Melt the butter in a saucepan and stir in the vinegar, thyme, salt, and pepper. Pour over the onions. Bake for about 20 minutes, and then turn the onions over and baste them with the pan juices. Bake for another 20 to 25 minutes until easily pierced with a paring knife and the inner rings have begun to swell and rise up.
Serve immediately or at room temperature.