Peel the completely cooled boiled potatoes. Use a box grater to grate them into a large mixing bowl. Grating prevents large lumps and ensures an even texture.

To the grated potatoes, add the cornstarch, grated ginger, chopped green chili, coriander leaves, red chili powder, roasted cumin powder, chaat masala, amchur, and salt.

Use your hands to gently combine the ingredients until they form a cohesive dough-like mixture. Do not overwork or knead vigorously, as this can make the mixture sticky.

Divide the potato mixture into 8 equal portions. Roll each portion into a smooth ball between your palms, then gently flatten it into a patty about 1.5 cm (1/2 inch) thick. Smooth any cracks along the edges to prevent the oil from seeping in.

Heat 3 tablespoons of neutral cooking oil in a wide frying pan over medium heat. The oil should cover the bottom of the pan in a thin layer.

Once the oil is hot and shimmering, carefully place 4 patties into the pan, leaving space between them. Fry on medium heat for about 4 to 5 minutes, until the bottom is a deep golden brown and crisp.

Gently flip the patties using a flat spatula. Fry the second side for another 4 to 5 minutes until it is equally crisp and golden brown. Repeat the frying process with the remaining patties, adding a splash of oil to the pan if needed. Transfer to a paper-towel-lined plate to drain before serving.