Is that not Hollandaise sauce? No, that is Béchamel sauce. They both belong to the mother sauces of French cuisine and they both contain copious amounts of butter, but Hollandaise sauce and Béchamel sauce are not the same.
Hollandaise sauce is an emulsion. Egg yolks are added so that lemon juice and melted butter can be combined without separating. Béchamel sauce does not contain eggs. It has flour. Butter and flour are cooked to form a roux to which milk is added.
Roux? Yes, it’s pronounced roo. You melt butter in a pan and, once fully melted but without allowing milk solids to separate from the fat, you add an equal amount of flour all at once.
You mix the butter and flour together until it forms into a paste. The paste is cooked before the liquid is added. Roux can be white, blonde or dark depending on how long the butter and flour are cooked together. To make Béchamel sauce, you need a blonde roux.
Once the roux is ready, you start adding milk. Slowly and with constant stirring.
Don’t worry if the mixture turns lumpy. That’s how it should be after the first addition of milk. Just keep adding more milk, slowly and with non-stop stirring.
The yellowish mixture will turn off-white after a minute or two but it will still be lumpy and too thick to be pourable. So, you continue to add more milk until the mixture acquires the consistency of a thick but pourable sauce. Then, you season. And, as a finishing touch, you stir in a little grated nutmeg.
- In a saucepan, melt the butter.
- Add the flour, all at once.
- Stir the butter and flour mixture until smooth.
- Cook over medium heat, stirring occasionally, for five minutes to make a blonde roux.
- Pour the milk in a thin stream, mixing as you pour. Don’t worry if the mixture turns out something like mashed potato at this point.
- Keep pouring the milk, and stirring, until all the milk has been fully incorpotated.
- Season the Béchamel sauce with salt (see notes after the recipe) and pepper.
- Stir in a pinch of grated nutmeg.