Cured cod dish

Beat the cod with a meat hammer and soak for 2 days in a large amount of cold water, changing the water several times. The fish is then peeled, rolled up and bandaged. Cook 1 hour with high boiling in a large amount of water. Melt 50g of oil in a saucepan and fry the onion in it until golden over a low heat. Melt 25 g of oil separately and mix with flour, add 0. 5 l of cod decoction, boil for a few minutes and add the remaining oil in pieces. Rub the mustard with a little sauce, gradually stir in all the sauce. Remove the fish rolls with a spoon from the pan, remove the threads and place on a heated plate. Separately, serve the boiled potatoes, crumbly rice and mustard sauce.