Cut off the central vein of the banana leaves, trim the edges. Warm the leaves over a very low flame, taking care to not char or burn the leaves. (This softens the leaves and keeps them flexible, making the parcels is much easier that way.) Cut the leaves to small pieces.

Shred the cabbage finely, soak in hot water with a pinch of salt and allow to rest in the water for about 30 minutes. Drain the water, squeeze any excess water from the shredded cabbage, keep aside.

Soak the yellow mustard seeds, black mustard seeds and posto in warm water for 15 odd minutes. Drain the water. Make a smooth paste with 3-4 green chillies, a pinch of turmeric powder and a couple of grains of rice, keep aside.

Soak the gobindobhog rice in warm water for 15 odd minutes. Drain the water. Grind to a coarse paste with very little water, keep aside.

Take the mustard-posto paste, gobindobhog rice paste, remaining green chillies, turmeric powder and 2 1/2 tbsp mustard oil in a big bowl, mix well. Add the chopped cabbage and green peas, sprinkle in the salt, another hearty mix.

Take a piece of banana leaf, add a small portion of cabbage and peas mixture in the middle.

Wrap the banana leaf from all four sides to make a parcel, secure with twine. (Or if you are in a hurry and want a shortcut, use tooth-picks instead to secure the parcels.)

Add ½ tbsp mustard oil to a flat pan, gently place the banana leaf parcels on the pan, cover with a lid and cook over a low flame for 12-15 minutes.

Serve hot with steamed rice.