Fried in vegetable oil. We like sunflower oil, but any kind of vegetable oil is valid. Pre-heat the oil at 180 C. You can cook them straight from the freezer or thawed. At the end, leave them resting on paper towel for a couple of minutes to drain excess oil. Deep fry in a small saucepan. Fill the saucepan with enough oil to cover the croquetas and pre-heat. Once the oil is hot (180 C), place the croquetas in and ensure they do not touch each other. Cook for approx. 4 min or until golden.  Shallow fry in a frypan. Fill the pan with enough oil to cover half a croqueta and pre-heat. Once the oil is hot (180 C), place the croquetas in and turn to coat all sides in oil.  Fry for approx. 4 min gently turning from time to time until golden. Check this video to see how to fry croquetas: How to fry croquetas. In Air Fryer Spray the croquetas with vegetable oil. Pre-heat the air fryer at maximum temperature for 3 min. before introducing a small number of pieces on the basket. Settings will vary depending on brand and model of your air-fryer and its power and size. You might have to find out the right time and temperature for your machine. As a reference, we cook them at 200 C for approx. 13 min plus another 4 min at 180 C. Gently turn around the croquetas from time to time until golden.