Heat the oil in a large heavy-based pan, over a medium high heat. When hot, add the bay leaves and, after 30 seconds, add the chopped onion. Stir well, cook for 1 minute then add the sugar, cook for a further 3 minutes until the onions are translucent.
Add the garlic and ginger and cook, stirring for 2 minutes. Then add the potato and cook for 4 minutes, stirring, until the potato starts to go translucent on the sides.
Increase the heat to high, add the lamb and break up with a spoon, taking care not to break the potatoes. Once the lamb has started to brown, add the turmeric, cumin, coriander, and chilli. Stir gently for 2 minutes.
Add the chopped tomato, tomato purée and pepper, mixing thoroughly. Cook for 4 minutes more - the juices should start to release from the ingredients.
See Notes to 'get ahead', if preparing ahead. Reduce the heat to low and mix in the peas, salt, garam masala and 100ml water. Cover and simmer for 15 minutes. Remove the lid and stir well, making sure excess liquid has evaporated and the mince is in a minimal but richly flavoured sauce. Transfer to a serving dish and garnish with the chopped coriander.