Add cabbage and onions to skillet or Dutch oven with water or broth and bring to boil. Cook for 10 minutes on medium heat. Add vinegar and salt. Turn heat to low and cover. Cook about 15- 20 minutes until just tender crisp, not soft and limp. Remove from heat and season with fresh ground pepper. Vegan butter can also be used at the end for extra flavor if desired. Cabbage has a natural buttery, sweet flavor that is wonderful.