Combine cabbage, celery, peppers, onion, and parsley in a large bowl and set aside.
Combine remaining ingredients in a small saucepan. Place over medium heat and cook just enough to melt the sugar. Pour over vegetables, give it all a good stir, and allow to sit at room temperature for 30 minutes before refrigerating to blend flavors.
Recipe from Who Wants Seconds: Sociable Suppers for Vegans, Omnivores and Everyone in Between, Prospect Park Books. Cover photographer David Kiang.