Roasted Red Onions

6 tbsp butter or margarine
2 1/4tsp red wine vinegar
1 1/2tbsp extra-virgin olive oil
2 1/4tsp brown sugar
1/2 cup honey
1/2 bunch fresh thyme
to taste Kosher Salt
to taste ground black pepper
4 halved red onions

Preheat the oven to 350 degrees F. Combine the butter, vinegar, oil, sugar, 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. Serve with fish and potatoes.