Heat oil in a pan add mustard seed, black gram, dry chili (broken into pieces). Once the mustard seeds stop splattering add onion, green chili and sauté until the onion turns translucent (golden brown).
Now add the cabbage and sauté until the raw smell is gone.
Now add tomato, coconut, tamarind, salt and sauté for 4 minutes and remove from heat (stove). Once this is cooled to down (room temperature) grind into a fine paste and serve.