Soak the cut cabbage in cold water while you prepare the remaining ingredients.
Heat the butter in a very large, deep skillet over medium-high heat. Once melted, add the onion and a pinch of salt and cook, until just about tender, about 3 minutes.
Add 2 TBSP of the red wine vinegar and cook for 3 minutes longer.
Add the apples and cook for 3 minutes longer.
Drain the cabbage and add it to the skillet along with the brown sugar, remaining 1 TBSP red wine vinegar, and a pinch of salt. Toss together.
Cover the skillet, and reduce heat to a simmer. Cook for one hour, stirring occasionally.
Season with salt and pepper, to taste.
