For the pickled tomatoes with white cabbage and onions, cut tomatoes, white cabbage and onions into strips. Halve the peppers, remove the seeds and cut them into strips as well. Boil the cut vegetables with water, vinegar, oil, sugar as well as some sea salt in a pot and stew for about 10 minutes.
Pour the pickled tomatoes with white cabbage and onions into hot rinsed canning jars, close tightly and turn upside down. Store in a cool and dark place.