Wash and rinse the potatoes. Slice them in approximately 2 mm/0.08-inch thickness. 

Rinse the sliced potatoes and soak them in a mixing bowl with fresh water. This will help the potatoes stay fresh and do not go brown due to the oxidation process. Set aside.

In another mixing bowl, put the gram flour, chapati flour (or rice flour), and all the spices and salt. 

Finely chop the bird’s eye chillies if using and add them in the flour.

Chop the coriander leaves finely and put them in the flour mixture.

Stir the flour mixture and pour the water in little by little as you stir. You may not need to use all it. Mix the flour until you get a smooth batter. You want to achieve the consistency of heavy cream/ double cream. Use your judgement if it’s thicker and need more drops of water. 

Heat the oil in a deep frying pan or a wok at moderately high heat. Test the oil temperature by dropping a little bit of batter in the oil. If the batter fries up steadily, your oil is ready. If it fries very fast, the oil is too hot so you may want to turn the heat down for a bit. 

Take some of the potatoes slices, drain the water and put them in the batter. Ensure they are covered with the batter. Then carefully slide the potatoes in the hot oil. Fry them until they go light golden and turn them once.