"Caramelized" Kielbasa

Here's another easy, internet found recipe that quickly became a favorite among my family (especially my Uncle Jeff). Can you tell we love our kielbasa?

2 lbs. kielbasa, sliced 1/4 in. rounds
1 lg. onion, yellow or sweet, sliced thinly
1 cup apple cider vinegar (any kind works)
1 cup brown sugar, packed

In large covered skillet, mix vinegar and sugar. Heat on medium until sugar is melted. Add onions and kielbasa. Cook 15 minutes covered, stirring once or twice to coat all kielbasa. Cook uncovered 5-10 minutes more. Keep an eye on it because it doesn't take long to "over cook" and become too sticky. Serve on platter or bowl with toothpicks. Serve over egg noodles or rice for main course. Serves 6-8. (Can easily be cut in half.)