Fillet the mackerel or have a fishmonger prepare them for you.
Boil 450g of new potatoes in salted water with reserved dill stalks until tender.
Coat the fish fillets in seasoned flour and shake off the excess.
Heat 25ml of oil and a small portion of butter in a frying pan.
Fry the mackerel fillets for 3 minutes on each side until cooked through.
Remove the mackerel from the pan and keep them warm.
Discard the used oil and melt the remaining butter until it turns nutty brown.
Stir in the juice of half a lemon and pour the brown butter over the fish.
Season with salt, sprinkle with chopped dill, and serve with lemon wedges.