Bechamel. White sauce for your lasagna or most of the food preparation. Homemade makes the difference. Delicious. No comparison with the one you buy.
In a pan melt the butter at low heat. Then slowly add the flour, stirring.
Once you obtained a firm mix, add the milk previously warmed up. Keep mixing trying not to form clumps. Mix till it tickens.
Add some grated nutmeg and salt. Ready!
The texture of the sauce should be thick if you use it for fillings, semi-liquid instead if you are using it for dressing.