1: Preheat the oven to 200°C/Fan 180°C/Gas 6. Place the lamb mince in a large roasting tin and roast, stirring 3 or 4 times to break up the mince, for 35–40 minutes until dark brown. It should look like instant coffee granules. Bake the merguez sausages in another roasting tin, alongside the lamb, for 10–15 minutes until cooked through.
2: Tip the mince into a colander to drain. Let the sausages cool, then cut into chunks.
3: Pour a splash of oil into a large saucepan and warm over a medium-low heat. Add the onions and garlic and sweat gently, stirring from time to time, for 10–15 minutes until soft. Stir in the fennel seeds, curry powder, cracked pepper and cinnamon and cook, stirring, for 2–3 minutes.
4: Stir in the celery and browned mince. Pour in the stock and add the Worcestershire sauce and some salt. Bring to the boil, lower the heat and simmer for 1–1½ hours, until beautifully thick and rich. Take off the heat and allow to cool.
5: Preheat the oven to 190°C/Fan 170°C/Gas 5. Stir the chopped sausages into the cooled lamb, then spoon into a shallow ovenproof dish, about 30 x 22cm and 8cm deep. Level the surface with the back of the spoon.
6: For the topping, bring a pan of lightly salted water to the boil, add the cauliflower florets and simmer until tender, about 5 minutes. Drain the cauliflower and place in a food processor with the butter, cream and some salt and pepper. Blend until smooth. Add the blue cheese and blitz to combine.
7: Spoon the cauliflower topping evenly over the lamb and sausage mixture. Stand the dish on an oven tray and bake in the oven for 30–35 minutes until the meat mixture is bubbling and the topping is starting to brown. Serve immediately.