- Place the star anise, cloves and thyme in one layer of cheesecloth. Tie in a bundle. Set aside.
- In a saucepan, soften the onion and garlic in the butter. Add the curry powder, ginger and meat. Coat with the spices. Season with salt and pepper.
- Add the broth, carrots, turnip, tomato and spice bundle. Bring to a boil and simmer over medium heat for 30 minutes. Remove the spice bundle. Adjust the seasoning. Set 60 ml (1/4 cup) of sauce aside. Transfer the curry in a 33 x 23-cm (13 x 9-inch) baking dish.
- With the rack in the middle position, preheat the oven to 170 °C (325 °F).
- With a mandolin, thinly slice the potatoes and arrange in a rosette on the lamb. Drizzle with reserved pan juices. Season with salt and pepper. Bake for about 2 hours.