Adapted from Iceland Food Centre

Peel potatoes, cut into large chunks and then place in boiling water in a large pot and cook for 15-20 minutes until soft enough to piece with fork.
While potatoes boil, in a small sauce pot put a small amount of butter in the pot and saute the onions. Once the onions have sweated, add the flour and whisk for 60 seconds.
Turn the heat down very low, add the milk and allow to cook until it thickens, about 4-5 minutes. Set aside.
Put another pot of boiling water up and once it boils place the fish in and cook for 8-10 minutes until the fish is completely poached. Drain.
Once the potatoes are soft, drain them, place back in the pot and mash and then put the fish and bechamel sauce in with the potatoes and mix until the fish completely flakes apart.
Serve hot with rye bread.
0 servings