Mash the potatoes and then add the green chillies, ginger, garam masala, sesame seeds, lemon juice, sugar, salt and coriander and mix together well. Roll the mixture into around 15 balls. I make them just a little larger than a golf ball in size. If you have time, pop them in the fridge to firm up for about 30 minutes.
When you are ready to fry, mix together all the batter ingredients i