- 6 tablespoons unsalted butter
- 1 1/2 pounds red onions, halved lengthwise, then cut lengthwise into 1/4-inch-thick slices
- 1 (3 pound) head of red cabbage, cut lengthwise into wedges and wedges cut crosswise into 1/4-inch-thick slices
- 2 cups dry red wine
- 2 cups water
- 1/4 cup red-wine vinegar
- 1/4 cup balsamic vinegar
- 1 firm sweet apple, such as Honey Crisp, Gala, or Fuji, peeled and coarsely grated
- 1 1/2 tablespoons sugar
- 1 1/4 teaspoons salt
- 10 whole black peppercorns
- 2 whole cloves
- 1 Turkish bay leaf
- Heat butter in a 6- to 8-quart wide heavy pot over moderately high heat until foam subsides, then cook onion and cabbage, stirring frequently, until wilted and slightly browned, about 20 minutes.
- Add wine, water, vinegars, apple, sugar, and salt and bring to a boil.
- Wrap peppercorns, cloves, and bay leaf in cheesecloth and tie with string. Add to cabbage mixture, then cover cabbage directly with a round of parchment or wax paper and cover pot with lid. Reduce heat and simmer until cabbage is very tender, about 2 hours.
- Discard cheesecloth bundle and season cabbage with salt and pepper.