This recipe is one that I found on the internet and is credited to Martha Stewart~so you know it is awesome! (and it is even awesome after the slight alterations I made to it.)
In a heavy pot, melt butter over medium heat. Add onion and apple; cook, stirring, until onion softens, 4-6 minutes. Stir in red cabbage and season with salt. Add cider vinegar, honey, and water. Bring to a boil; reduce heat to a simmer, cover, and cook until cabbage is tender, 20-25 minutes. Taste. Add salt and/or honey as needed.