Heat the vegetable oil in a large saucepan until hot, add the lamb and brown on all sides. Add the curry powder and cumin seeds and cook for a minute.
Remove pan from the heat. Add the crushed garlic and vegetables. Lower heat to medium and return pan, then cook gently for 3 minutes before adding the lentils, water, chicken stock cube, bouquet garni, salt and pepper.
Bring to the boil then reduce to simmer. Simmer for 45 minutes to an hour until the lentils are cooked and soft in texture. Complete the dish by mixing in the plum chutney.