Heat some of the olive oil in a frying pan and brown off the leeks and garlic.
Remove from the heat and add the mashed potato along with the egg yolk and corned beef. Mix well.
Coat your hands in a little flour so the potato doesn't stick, and form the mixture into four equal patties, approximately 5cm/2in in diameter. Add salt and pepper and shallow fry the patties in a little more olive oil until golden brown on both sides.
To make the chutney, heat a saucepan with a drizzle of olive oil, the red onion and the chilli. Cook until browned.
Add the tomato, brown sugar and seasoning, and allow to caramelise for five minutes.
Serve either hot or cold with the potato cakes and some ripped salad leaves.