For the plaice, season the plaice with salt and freshly ground black pepper. Dredge the fish in the flour, shaking off any excess.
Heat the olive oil in a frying pan and fry the plaice fillets skin-side down for 3-4 minutes. Turn over and cook for a further 1-2 minutes, or until the fish is cooked through. Remove from the pan and set aside to rest on a warm plate.
Heat the butter and lemon zest in the frying pan used to cook the fish, stirring until the butter is melted and turns a nut-brown colour. Remove from the heat and stir in the capers, parsley and lemon juice.
For the creamed cabbage, place all of the cabbage ingredients into a pan and bring to a simmer. Cook for 8-10 minutes over a low heat, or until the cabbage is tender.
To serve, spoon the creamed cabbage on a plate, arrange the plaice fillet pieces on top and spoon over the caper butter.