Chop the lamb into cubes and set aside. Finely chop the onion, mince the garlic, and grate the ginger.

In a large pot, heat the vegetable oil over medium heat. Add the chopped onion and saut? until translucent.

Add the minced garlic, grated ginger, bruised lemongrass, and torn lime leaves. Cook for another 2-3 minutes until fragrant.

Stir in the ground coriander, cumin, turmeric, cinnamon, nutmeg, and chili powder. Cook for 1-2 minutes to toast the spices.

Add the lamb cubes to the pot and stir to coat with the spice mixture.

Pour in the coconut milk and stock, then add the brown sugar and salt. Bring to a boil, then reduce heat to low and simmer for about 1.5 hours, or until the lamb is tender.

Once the lamb is tender, adjust seasoning if necessary. Serve hot with rice or flatbread.