6 tablespoons butter
3 tablespoons balsamic vinegar
1/2 cup honey
1/2 bunch fresh thyme
Salt and freshly ground black pepper
4 red onions, halved
Preheat the oven to 350 degrees F.
Combine the butter, vinegar, honey, thyme, salt, and pepper in a small saucepan over medium heat.
Bring to a simmer and cook for 1 minute to reduce slightly.
Place the onions, cut sides up, in a single layer on a baking pan.
Drizzle the butter-vinegar mixture over and roast until soft and slightly caramelized, about 45 minutes.