Boil 500 grams of potatoes until they are soft and cooked. Peel and mash them well, ensuring no lumps are left.
In a pan, heat 2 tablespoons of oil. Add 1 teaspoon of mustard seeds and let them splutter. Then add 1 teaspoon of cumin seeds, a pinch of asafoetida, and 1 finely chopped green chili.
Add 1 finely chopped onion and sauté until it turns golden brown. Add 1/2 teaspoon of turmeric powder, 1/2 teaspoon of red chili powder, and salt to taste. Mix well.
Add the mashed potatoes to the pan and mix well with the spices. Cook for 2-3 minutes, then add chopped coriander leaves. Turn off the heat and let the mixture cool.
In a bowl, prepare the batter by mixing 1 cup of gram flour (besan), 1/2 teaspoon of red chili powder, a pinch of baking soda, and salt to taste. Gradually add water and whisk until you get a smooth, thick batter.
Heat oil for deep frying in a kadai or deep pan. Make small balls from the potato mixture and dip them in the gram flour batter, ensuring they are evenly coated.
Carefully drop the coated potato balls into the hot oil and fry them until they turn golden brown and crispy. Remove them from the oil and place them on a paper towel to drain excess oil.