Savoy cabbage has crinkled, pale green leaves and mellow flavor; you can also use napa (Chinese) cabbage, which has a similarly mild taste. Look for sherry vinegar in specialty or gourmet stores; if you can't find it, substitute cider vinegar.
Heat the olive oil in a Dutch oven over medium heat. Add cabbage and water; cook 6 minutes or until cabbage wilts, stirring occasionally. Stir in salt and black pepper.
Place cumin seeds in a small nonstick skillet; cook over medium heat 1 minute or until seeds are toasted and fragrant, shaking pan frequently. Add the toasted cumin seeds and vinegar to cabbage; cook 6 minutes or until tender, stirring mixture occasionally.