Take a blender jar, put in a handful of coriander,mint,green chilli and ginger and a glass of water and blend to a paste. Strain it, and keep the residue aside. Residue is very flavorful, we'll use that in masala filling.

Take a big mixing bowl, add in the strained paste along with rest all the rest ingredients and mix well. Taste and adjust to taste. I adjusted mine by adding another ¼ cup tamarind pulp and salt, black salt, cumin. Pani is ready.

In a mixing bowl, add the potatoes and mash them. Tip in the onions, mint-coriander and all the other spices. Mix well and adjust to taste. Stuffing is also ready. Serve with crispy puris.

In a mixing bowl, add in the maida, suji, salt and baking soda. Mix and make a dough using sufficient water. Make a soft dough.
Once the dough is ready, cover and let it rest for 30 mins.
Heat oil to very high. Just before smoky point.
Make 3 portions out of it and then roll it thin. Roll it thinner than a chapati but not much thin otherwise it wont puff! Cut it using a glass.
Now drop these in very hot oil. Lower the flame and fry until golden.
Take the puris out.

Serve & enjoy Pani Puri.