Boil the potatoes (skin on) until tender, then drain and remove the skin.

Mince the walnuts, mint, coriander and chillies.

Place the potatoes in a plate and then mash them into a smooth paste using a fork, ensuring that there are no lumps. Add the walnuts, mint, coriander, chilli, salt, all the spices and the cornflour. Mix well.

Cut the avocado into half inch pieces. Take a golf-ball sized piece of the potato mixture, roll it into a ball. Make a deep indentation into the potato using a finger and place a chunk of avocado inside. Close the potato mixture around the avocado and roll smooth. Flatten the ball slightly and set aside on a plate. Make patties with the remaining potato mixture the same way.

Warm a fry pan with a tablespoon of oil. Place a few of the patties in the hot oil and cook on medium-high heat until the bottoms are deep brown. Turn once and let the other side brown up, adding another tablespoon of oil all around to ensure a crisp crust. Remove and serve with green chutney.