
Preheat oven to 180°C/350°F (160°C fan).
Mix curry paste, coconut milk and stock in a 22 x 33cm / 9 x 13" baking dish, preferably glass or ceramic (Note 5). Add onion, potato, star anise, cinnamon and lamb.
Turn shanks to coat in sauce, then cover with foil.
Bake in oven for 2 hours. Remove foil, bake for a further 1 hour (small shanks) or 1.5 hrs (medium to large shanks), turning lamb twice to brown evenly, until meat is so tender it can easily be teased apart with 2 forks.
Remove lamb onto plate. Carefully skim off excess fat off the surface (tilt dish, it's easier) - I get about 1/3 cup. Mix sauce in baking dish - it should be reduced down to a syrupy thickness (Note 6).
Serve lamb with sauce over jasmine rice, garnished with chilli and coriander. For a larger banquet, put the curry out on a platter to share!
Notes
Note on cooking method: This recipe is not suited to slow cooker, pressure cooker or stove. Achieving the intended flavour with such little effort requires the oven to caramelise the surface of the lamb and sauce (as well as reducing the sauce).
Lamb Shanks cook times for different sizes:
Small shanks 300g/10oz each x 5 = 2 hr covered, 1 hr uncovered
Medium shanks 350 - 400g/12 - 14 oz each x 4 = 2 hrs covered, 1.5 hrs uncovered Large hind shanks 600 - 750g / 1.2 - 1.5 lb each x 2 = 2 hrs covered, 1.5 hrs uncovered, USE
SMALLER BAKING DISH so liquid covers ~ 1/2 to 2/3 of meat
Small and medium shanks are foreshanks (front legs of lamb). Large are from the rear, called hind shanks.
Even though large hind shanks are twice the weight of medium shanks, they will cook to fall apart tender in the same time if they are mostly submerged in liquid as heat transference is efficient (as opposed to roasting exposed without liquid - larger size takes proportionally longer to cook).
about how it will suit the curry sauce!
Massaman curry paste - best is Maesri brand, sold at most Woolworths & Coles in Australia, as well as Harris Farms and Asian stores.
Coconut milk - the quality/flavour comes down to the % of the liquid that is actually coconut milk. Ayam is the highest at 89%, cheap ones can be as low as 45%.
Low sodium chicken stock - important to get low sodium because it cooks right down and concentrates the saltiness. If you don't have low sodium reduce by 3/4 cup and add 3/4 cup water instead.
Pan - clean up easiest with glass or ceramic because it will require a bit of scrubbing with a brush (it comes off easily after a brief soak). Metal would need to be soaked longer and scrubbed gently.
Sauce - if it's still a bit thin once meat is fall apart tender, just pop it back into oven without the lamb. Will reduce quickly. Keep lamb covered to keep it warm - lasts like that for ages.
If it's reduced down too much (eg if your dish was large and there's lots of sauce surface area exposed), just add boiling water to thin it out. Should have close to 3 cups (750ml) sauce (give or take - there's so much flavour in it, it won't matter if it's slightly thinner or thicker).
Storage / make ahead - as with all stews, this just gets better with time! Keeps for 4 to 5 days in the fridge, freezes for 3 months (thaw then reheat). Best way to reheat lamb shanks is to cover and reheat in oven at 180C/350F for 30 minutes or so, or microwave on low (high heat will cause large pieces of meat have a tendency to pop - don't do it!). Loosen sauce with more water if needed.
Nutrition per lamb shank, assuming 1/3 cup fat is scooped off and all curry sauce is used.