A recipe for White Tuna fishballs from ” Spain on a Plate” by Maria Jose Sevilla. You can use different fish if preferred.
Heat half the oil and fry the 2 chopped onions over a low heat until golden brown. Meanwhile soak the bread in the milk.
In a bowl mix the cooked onions with the bread, tuna, garlic, parsley and three eggs. Season to taste with salt. Mix to a paste and form into small balls with your hands. Dust with a little flour and coat with the remaining egg.
Heat the remaining oil and fry the fishballs, turning occasionally, for about 15 minutes until golden brown.
Meanwhile make the sauce. Bring the wine and the lemon juice to the boil and boil to reduce by half.
Melt the butter and fry the remaining onion for about 10 minutes until golden brown then stir in the flour and cook for a minute. Stir well, remove from the heat and leave to cool a little.
Return to the heat and add the reduced wine, a little at a time, and just enough fish stock to make a light sauce. Simmer gently for 15 minutes.
Serve the albondigas with the sauce to accompany.