Braised halibut with scallops and roasted potatoes

Preheat the oven to 200C/180C Fan/Gas 6. To make the olive oil roasted potatoes, put the potatoes in a saucepan of cold, salted water then place over a medium-high heat and bring to the boil. Boil for 2–3 minutes, then drain the potatoes and allow them to cool and steam dry before carefully crushing.

Place the crushed potatoes into a roasting tin along with the oil, bay leaves and garlic. Roast for 15–20 minutes, basting frequently, until crisp all over. When cooked, season with plenty of salt and muscatel vinegar. Keep warm and set aside.

To make the halibut, place 20g/¾oz butter in a flameproof casserole dish over a medium heat, then add the shallot and garlic and sauté for 2 minutes. Add the girolles and sweetcorn, then cook for 2–3 minutes before adding the wine. Boil off for 1 minute then add 50ml/2fl oz water. Sit the halibut on top of the mushrooms and cover the dish with a lid. Transfer to the oven and cook for 5 minutes.

After 5 minutes, add the sliced scallop to the dish and return to the oven for 2–3 minutes, lid on, until cooked.

When cooked, use a fish slice to carefully remove the fish from the dish and keep warm. Whisk in the remaining butter and some lemon juice into the sauce, then taste and season with salt and pepper. Stir in the chives and chervil.

Spoon the sauce into a bowl and top with the scallop and halibut. Serve with the roasted potatoes alongside and garnish with sprigs of watercress.