The last installment of my mother sauces series was so long ago you probably didn’t guess that this was going to be a series. However, I use this béchamel base all the time and it seems criminal not to share how easy and useful it is with those who are not already aware. Again, exact ingredients can vary slightly among the greats, including a particularly complicated version by Escoffier which recommends adding veal bits then straining them out, but the very basic details are straight forward:
In a saucepan, add 1 part white flour to 1 part melted butter (e.g. 2 Tbs. butter, melted, plus 2 Tbs. flour). Stir over low heat until combined and thick, about 1 minute [this is called making a roux]. Whisking constantly, add approximately 16 parts milk (i.e. 1 cup milk to every tablespoon of butter) in a slow stream until fully incorporated. If you like, you can warm up the milk with aromatics before blending with the roux – for example: nutmeg, bay leaf, thyme, or onion. This will infuse your sauce with a great depth of flavor; just be sure to strain the solids out before mixing the milk with the roux. Let sauce simmer over very low heat, stirring occasionally, until the sauce coats the back of a spoon (i.e. the sauce doesn’t slip right off of the spoon, and when you drag your finger through it, the trail stays put).
This has so many incredible applications, including recipes such as: Cauliflower Gratin, Baked Potatos with Gruyere & Broccoli Sauce, and Wild Mushroom Lasagne. I have used it too as a base for my creamed spinach (which is really a mornay sauce), and for my macaroni and cheese (though I may be replacing that recipe with this one as my new favorite).
From the béchamel base you can add cheese to make a cheese sauce, cream to make a cream sauce, or any sturdy vegetable to make a gratin. I often boil and mash winter squash then stir in a sage-infused béchamel to thin it out a bit and make for a more flavorful puree. A thin béchamel with lots of garlic aromas (like a Soubise sauce) can make for a killer shrimp pasta or the perfect topping for fresh mushroom ravioli. Let your imagination be your guide, but do try this to find out how easy and versatile it really is.