Before you begin, boil, peel and grate the potato. Keep it aside for now.
The first step is to add chickpea flour/besan to a mixing bowl.
Add chilly powder, turmeric powder, salt, cumin seeds, and ajwain/carom seeds. Mix all the masala together.
Add half of the water first. With a whisk/spoon give it a good mix so that there are no lumps formed. Then add the remaining water and make a thin batter.
Heat oil in a nonstick pan and pour this thin batter onto the pan. Immediately begin to mix it and lower the flame.
In about 2-3 minutes, this mixture will begin to thicken and not stick to the pan anymore. The key is to keep stirring it and cook it on low flame.
Once it comes together like a dough mixture, take it off the flame.
Let it cool down for about 5 minutes and then add the grated potatoes to it.
Also add salt, chopped cilantro, and minced green chillies. It will be a little hot but using your hands bring all of this together.
Grease a cookie tray or a plate as well as your palms. Spread and flatten the mixture evenly. The thickness can be a quarter or half an inch. Freeze it for 15-20 minutes.
Take out the tray from the freezer, and cut it into squares. You can cut them in any shape you want.
Heat oil for frying. Shallow-fry the squares on medium flame. It should turn golden on both sides. Transfer to a plate with paper towels to soak off the excess oil.
Serve the Besan Potato Squares hot along with some chutney, ketchup, mayo, or any other condiment of your choice.