Open the tin of salmon and reserve the brine (liquid). Combine the brine with the milk.
In a medium saucepan melt the butter and add the flour. Stir to combine and allow to cook for 1 minute.
Take the saucepan off the heat. Gradually add the milk mixture, a little at a time, strirring well after each addition, until all combined and you have a smooth sauce. Return to the heat and bring to a simmer, stirring constantly as the sauce thickens, to avoid lumps. Allow to simmer for 2 minutes and remove from heat.
Break up the salmon and remove any bones or skin. Add the salmon to the white sauce along with the parsley, spring onion, lemon juice, salt and pepper. Stir until combined. Taste and add more lemon juice or salt and pepper if required.
Spread the mixture onto a flat plate or casserole dish and place in the refrigerator for 1/2 an hour to cool and become firm. The longer you leave the mixture in the refrigerator, the fimer it will be for rolling into croquette shapes.
Take a tablespoon of mixture and place into the flour, roll and work into a cylinder shape, pat the ends flat or round them off. Dust of the excess, coat in the beaten egg and finish off in the breadcrumbs. You should have between 12 – 15.
Heat oil in a deep fryer, wok or saucepan, to medium heat. Add the croquettes and fry, turning, until golden. If the mixture starts to seep put, you may have your oil too high.
Serve with lemon or lime wedges and a salad.