Fry the onion with the 3 tablespoons of flour and the butter at medium fire, while stirring.

Once the onion is brown, add the serrano ham and milk slowly, until it integrates.

Using a spoon, make little balls with the mixture. Bread each ball putting it in the flour, followed by the egg and the ground bread.

Freeze the croquettes for 20 minutes. Meanwhile, heat the Sabrosano oil in a pot.

Fry each ball until cooked. Remove the excess oil with a paper napkin.

Serve hot and enjoy!