For the mash, heat a pan of boiling water over a high heat. When boiling add the sweet potatoes and the cumin seeds and boil until tender. Drain and mash adding the butter, cream and salt and freshly ground black pepper.
For the halibut, heat the olive oil and in a frying pan. When hot add the halibut and fry for 3-4 minutes on each side until cooked through. Then add the lemon juice.
For the sauce, place the white wine, cream, lemon juice and mustard together into a saucepan over a medium heat and simmer for two minutes. Add the chopped chives.
For the broccoli, heat the oil in a frying pan over high heat and stir-fry the garlic and chilli powder for one minute.
Add the broccoli and fry for another three minutes.
Add the tomatoes and cook for further one minute.
To serve, place the mash into the centre of a serving plate with the fish on top. Drizzle the cream sauce on top of and around the fish. Serve with stir-fried broccoli.