Boil the chopped chicken breast for 25 minutes.

Meanwhile, sauté the onion. Once it starts to brown, add the mushrooms, finely chopped so you don't get large pieces later.

Shred or chop the chicken breast and add it to the pan. Set aside while you make the béchamel sauce.

Heat the milk in a pot until it comes to a boil.

While the milk heats, melt the butter or heat the oil in a large pot (oil gives a stronger flavor, but I prefer butter). Add the flour and stir well, then gradually add the hot milk, stirring constantly until the mixture is smooth and reaches the desired consistency.

Add salt, a pinch of pepper, and nutmeg. Mix well.

Add the chicken and mushrooms to the béchamel sauce and mix thoroughly. If you can resist tasting it now, spread the mixture onto a tray, cover with plastic wrap, and refrigerate for a day.

Now it's time to shape and enjoy these delicious croquettes! Lightly oil your hands to prevent sticking, shape the mixture, then coat each croquette first in flour, then beaten egg, and finally breadcrumbs.

All that's left is to fry them. Enjoy!