Melt the butter in a medium saucepan over medium heat, then stir in 60g of flour and cook for 2 minutes to create a smooth, golden roux.

Gradually whisk in the warm whole milk a little at a time, stirring constantly to prevent lumps, and simmer until the béchamel sauce becomes very thick and smooth.

Fold in the finely chopped Serrano ham, wild garlic, and a pinch of nutmeg, then season with salt and pepper to taste before removing from the heat.

Spread the mixture into a shallow baking dish, press plastic wrap directly onto the surface to prevent a skin from forming, and chill in the refrigerator for at least 2 hours until completely firm.

Shape the chilled croqueta mixture into small, even-sized cylinders or logs using your hands or two spoons.

Roll each log lightly in flour, dip into the beaten eggs, and then roll in the panko breadcrumbs until evenly coated.

Heat about 2 inches of oil in a deep pan to 350°F (175°C) and fry the croquetas in small batches for 2 to 3 minutes until they are beautifully golden brown and crispy.

Drain the fried croquetas on paper towels and serve immediately while the center is warm, creamy, and oozing.