For the mash, place the potatoes in a pan of salted water and bring to the boil. Simmer until the potatoes are tender and then drain well and push through a ricer.
Return the potatoes to the pan over a low heat and then stir in the butter and cream. Season well with sea salt and freshly ground black pepper then slowly whisk in the olive oil until thoroughly combined. Set the pan aside in a warm place.
For the hake, heat a non-stick pan over a high heat and add a splash of olive oil. Season the hake darnes with sea salt and freshly ground black pepper and place them in the pan.
Sear on one side for two minutes, turn onto the other side and add the chorizo, shallots and clams.
Cook for a further minute until the chorizo has started to release its oil and the clams have started to open.
Drain off a little of the oil then add the sherry and wine. Bring to the boil and reduce the sauce then turn the hake again and add the butter and parsley.
Stir the sauce to emulsify it, scraping the sediment from the bottom of the pan to add extra flavour. The sauce should have a syrupy consistency and the hake cooked through – the flesh should be opaque when a small knife is inserted near the bone. Check the sauce for seasoning and add a squeeze of lemon juice.
To serve, spoon some of the mash onto a serving plate, top with the hake, spoon over the sauce and scatter around the clams and chorizo.