1. Heat the olive oil in a large pot over medium heat.
2. Add the chopped onion and cook until translucent.
3. Stir in the minced garlic and grated ginger, cooking for another minute.
4. Add the cubed lamb and cook until browned on all sides.
5. Mix in the curry powder, ground cumin, and ground coriander, cooking for another 2 minutes.
6. Pour in the coconut milk, tomato puree, and brown sugar. Stir well.
7. Bring to a boil, then reduce heat and let simmer for 45 minutes, or until the lamb is tender.
8. Season with salt and black pepper to taste.
9. Serve hot with rice or naan bread.