The bechamel sauce, commonly known as besciamella in Italian and simply as white sauce in English, is one of the most common sauces in some cuisines, such as, for instance, the Italian and French ones. This is the perfect bechamel sauce for lasagna, but not only!
Stir in the flour and mix until well-combined. Cook for 1-2 minutes.
Add the hot milk gradually while constantly stirring to remove the lumps. When all the milk has been added, keep stirring and season with salt and some nutmeg.
Bring to a boil and then reduce the heat. Keep cooking for 3-5 minutes until you have reached the desired thickness, a thicker sauce for fillings and slightly runnier for sauces, lasagna etc.