How to Make It
In a large stainless-steel saucepan, toss the shredded cabbage with the bell peppers, onion, celery and minced jalapeño. Add the vinegar, salt, mustard seeds, turmeric, celery seeds and sugar; bring to a boil. Cover, reduce the heat to low and simmer, stirring occasionally, until the vegetables just soften, about 20 minutes.
Transfer the relish to glass jars and let cool, then cover and refrigerate for 1 week before serving.