Remove the tender leaves from the stems as shown in the picture. Finely chop the leaves. Keep aside.
Cut the stems into 2-inch pieces. Keep aside.
Wash thoroughly, pressure cook the stems and leaves together with a splash of water. 2 whistles, I would reckon. Allow the steam to release on it its own.
Soak the yellow mustard, black mustard and poppy seeds in warm water for 15 odd minutes. Grind with 3-4 green chilies to a smooth paste. Keep aside.
Heat 2 tbsp oil in pan, when smoking hot, throw in the kalonji and the remaining green chilies. Allow them to splutter.
Gently add the steamed greens and the stems along with the juices to the pan.
Sprinkle in the salt and turmeric powder, cook till the juices almost dry off.
Add the mustard-poppy seed paste, give it all a hearty stir. Continue to cook for a further 4-5 minutes.
Throw in the fried boris, mix gently. Finish with a generous drizzle of mustard oil.
Serve hot with steamed rice.