Pour milk into the pan and heat it (no need to boil).

Melt the butter in a pan (make the fire medium or slightly less than medium).

Add flour and mix well with a wooden spatula.

Gently, in small portions, pour in milk, intensively stirring the sauce, so as not to form lumps.

Bring sauce to a boil, stirring and simmer for 1-2 minutes. The sauce should thicken. Salt

Turn off the heat and put the butter pieces into the sauce to prevent the formation of a film on the surface of the sauce.