Preheat the oven to 180C/350F/Gas 4.
For the spicy crusted monkfish, grind the cardamom seeds, coriander, cumin and chilli together in a pestle and mortar. Transfer the spice mixture to a hot dry pan and toast for 2-3 minutes, shaking the pan frequently to prevent burning, until the spices are golden-brown and aromatic. Tip onto a plate and roll the monkfish in the spices, coating evenly.
Heat the olive oil in an ovenproof frying pan, then fry the monkfish for 2-3 minutes on both sides, or until golden-brown. Transfer the pan to the oven and roast for a further five minutes, or until the fish is cooked through. Remove from the oven and leave to rest for five minutes before thickly slicing.
For the broad bean purée, heat the oil in a frying pan and lightly fry the onion and garlic for 2-3 minutes, and then add the broad beans. Season with salt and freshly ground black pepper, then pour in the boiling water. Transfer the mixture to a food processor and blend until smooth, then return to the pan, stir in the cream and heat through.
For the sautéed potatoes, parboil the new potato slices in boiling water seasoned with the ground turmeric for five minutes, then drain well. Melt the butter in a frying pan until frothing, then fry the potatoes for 5-6 minutes, or until tender and golden-brown.
To serve, pile the sautéed potatoes onto a serving plate and top with the sliced monkfish. Drizzle the broad bean purée around the plate and garnish with the fresh dill.