Besciamella is used in classic Italian dishes like Lasagna Bolognese.

Once you master the sauce you will see how easy it is to create many versions of it by adding mushrooms, herbs, Parmesan cheese, tomato ....the possibilities are endless.

Visualize this sauce with pulled roasted chicken and sauteed mushrooms with a touch of truffle oil or a splash of Marsala, as a pasta sauce or poured into a puff pastry shell.....get the picture?

The most important technique is to add hot milk to hot roux.  Doing this slowly and whisking quickly will prevent lumps....you don't want dumplings in your Besciamella, not good. 

Never fear if you do have some lumps you can pass the sauce threw a strainer then whisk it further to make it smooth.

Ingredients

1/2 gal Whole Milk

4 oz All purpose flour

4oz Whole sweet butter

1/2 ea  fresh medium yellow onion chopped very fine

ground white pepper taste

pinch ground nutmeg

kosher salt taste

Method
Heat your milk to under a simmer.
In a suitable sized thick bottom sauce pan add your butter and heat it until it is melted.
Add in your chopped onions and cook till translucent.
Proceed to add your flour little by little until it forms a paste.
this "roux" will now be cooked for 5 min or so untill it rolls off the side of the pan.

Now lower the heat and gradually add the heated milk into the roux whisking quickly to prevent lumps.

It will get thick right away so keep on adding your milk.

Once all your milk is incorporated then the sauce will continue to thicken.

Less roux thinner sauce, more rough thicker sauce.

I have to tell you I have scorched many a besciamella in my time to be sure you use a thick bottom pan and whisk quickly.  I'm sorry to say if it starts to stick on the bottom it most likely will scorch and all will be lost. 

There is now way to recover from a scorched sauce.  Believe me I have tried!

Of course you may want to take the easy way out and just reduce heavy cream like we did in the 80's where everything was a cream reduction sauce! ☺