Drain and mash the soyabean granules. Place the wheat flour and salt in a bowl, add sufficient water and knead into a soft dough. Cover with a damp cloth and rest for about half an hour.
Heat oil in a non-stick pan. Add the onion and sauté till light brown. Add the turmeric powder, green chillies and soyabean granules and mix well. Add the milk and stir to mix. Set aside to cool.
Place the mashed potatoes in a bowl, add the soyabean mixture and salt and mix well. Divide into eight equal portions. Divide the dough into eight equal portions and roll into a ball.
Place a portion of the soya granule mixture in the centre, gather the edges and shape into a ball again. Dust each ball in flour and roll into a parantha.
Heat a non stick tawa and place a parantha on it. Cook for half a minute, flip and drizzle a little oil all around and cook for a minute.
Flip again and drizzle some more oil all around. Cook till both the sides get cooked evenly golden.
Serve hot with dollops of butter.