Dice the onion in small cubes, take to the pan and sauté with a little oil until semi transparent.

Open tuna cans and drain throughly, put tuna in a large mixing bowl.

Add onion, parsley and 2 eggs to the bowl. Mix well, preferably using you hands. Salt to taste.

Separate the mix in 8 equal parts and shape them to look like hamburgers.

In a small bowl put the remaining egg and mix white and yolk together. Put bread crumbles in a similar bowl.

Bathe the croquettes in the egg mix, then in bread crumbles, making sure they are completely covered each time.

In a pan, put enough oil to cover the bottom with a thin layer. Fry each side of the croquettes for three minutes or until gently browned.