Method
Prep:15min  ›  Cook:5min  ›  Ready in:20min 

1. Peel the onions and half lengthwise. Thinly slice onion halves. Place onion in a bowl of ice water, and let soak for 5 minutes. Drain well in a colander.
2. In a large heatproof bowl, toss together the green and red cabbage, onion, carrot and vinegar.
3. In a small frying pan, heat the olive oil over moderate heat until it is hot but not smoking. Add the caraway and mustard seeds, and cook, covered, stirring occasionally, for 1 to 3 minutes, or until the mustard seeds stop popping. Drizzle the hot oil mixture immediately over the cabbage mixture and toss the coleslaw well. Add salt to taste and toss again. Chill before serving.