Шаг 1
Put the milk on low heat, add the onion, and simmer for 20 minutes.
Шаг 2
Heat the butter and mix it with the flour, stirring constantly until smooth.
Шаг 3
Remove the onion from the milk, pour the milk in a thin stream into the flour-butter mixture while constantly stirring. Simmer over low heat for 30 minutes.
Шаг 4
Add salt and pepper. Strain the sauce through cheesecloth.
Шаг 5
Done! Béchamel sauce is ready. If you need more, for example for lasagna, double the ingredients. And if you add 30 ml of hot cream and a few drops of lemon juice, you’ll get a Cream Sauce.