In a non-stick skillet, heat the olive oil and saute the onion and garlic until translucent.
Add the cod and cook for a couple of minutes.
Add the flour and cook for a couple more minutes.
Add the milk and stir until thoroughly combined. Cook for 10 minutes, stirring frequently so it doesn’t stick to the bottom.
Transfer the mixture to a paper-lined baking tray and spread it into a rectangle - it should be around ½ inch thick. Cover it with a wrap so it doesn’t dry.
Refrigerate for 1 hour or until it hardens.
Cut the mixture into cubes ( 1 ½ inches).
Coat each cube in the flour, then in the eggs, and lastly in the breadcrumbs. Use your hands to form them into a ball.
Heat the oil to 180ºC and fry them until golden brown on each side.
Transfer to kitchen towels to remove excess grease and serve.