This Sri Lankan recipe can be made with all kinds of vegetables: kale, broccoli, okra, carrots, etc. The important thing is to slice the vegetables thinly.
Heat coconut oil in a pot on medium. Fry mustard seeds for a few minutes then add curry leaves. Add shallots. Stir well and sauté for 1 minute.
Add remaining ingredients. Stir well, cover, and simmer on low heat for 15-20 minutes until the cabbage is falling apart.
A variation of the Shafi's Steamed Beets from The Spice Trekkers Cook at Home