In a bowl, add potato. In a grinder, add green chili, coriander leaves, ginger, and garlic, grind it to make a fine paste.
Add ground chili-coriander paste, turmeric, dry mango, cumin, fennel powder, asafoetida and red chili flakes in the bowl.
Add kalunji (Nigella seeds), salt and corn flour in the bowl. Mix it well.
Divide the mixture into 10-12 equal portions and make the smooth balls. In a plate add semolina. Roll each ball in the semolina for coating.
Heat the wok/kadai with oil and deep fry 4-5 balls at a time on a medium to low flame.
Fry it till it is golden and crisp. Take out the fried balls on a tissue paper to get rid of the extra oil.
Deep fry all the balls in the same way, and enjoy it with your favourite dip.