Heat 2 tablespoons of extra-virgin olive oil in a pan over medium heat. Soften 1 small finely chopped onion and 3 minced garlic cloves.
Stir in ¼ cup of all-purpose flour and cook briefly. Gradually stir in 1 cup of low-fat milk until a thick paste forms.
Off the heat, stir in 100g of finely chopped jamón ibérico and season with nutmeg, salt, and pepper. Chill for at least 30 minutes.
Shape into egg-sized cylinders. Roll in ½ cup of all-purpose flour for coating, dip in 1 beaten egg mixed with 1 tablespoon of milk, then coat in 1 cup of plain breadcrumbs.
Heat 1 cup of olive oil for frying in a frying pan. Fry the croquettes in batches for about 3 minutes per side, until golden, and drain on paper towels.
