Remains of a filleted hake (head, bones, fins, abdominal section) we put in one liter of cold water. We add olive oil, salt, pepper, parsley, white onions, red onions and cook on a strong flame for 30 minutes. After that we lower the flame and cook for another 30 minutes. We strain the soup, finalize the flavor and put it back on the flame while adding fish-balls.
We make the fish-balls by soaking a piece of stale bread, crush it in our hand and add salt, pepper, parsley, hake liver and roe with an egg yolk and a bit of olive oil.