I had been wanting to try carmelized onions in the crock pot, so I appreciated the recipe for that alone. The smell was fabulous in my kitchen all day. I thought the beef broth was a nice touch. I went ahead and added the balsamic vinegar directly to the crock pot before serving. I have lots of leftover onions that I will put to good use. I added some steak seasoning to the hamburger mixture. Thanks so much for the delicious recipe. Roxygirl in Colo.