Bechamel sauce is a basic white sauce. I like to add cheese, pepper, and some herbs to it for lasagne, otherwise it just tastes, well … white. And that’s not much fun. It’s a little fiddly if you’re doing it from scratch, but not too difficult. It does require a lot of stirring, and you really can’t walk away from it at any point, though. Make sure you have a good twenty minutes up your sleeve before you start.
Here’s our cast: butter (I always use unsalted), plain flour, cracked pepper, reduced fat cheese (I’ll tell you why in a second), milk (any kind is fine. I’m using reduced fat) and some fresh herbs – parsley and chives.
The amount of sauce you end up with is dependent on the amount of butter you start with. I don’t measure anything (you’ve probably already noticed that), but this is about 100g. I would use more rather than less if you’re unsure.
Once the butter is completely melted, grab a heaped tablespoon full of flour. It pays to have your flour right next to the stove, you can stir with one hand and grab flour with the other. You do need to work reasonably quickly, at least to start with.
Quickly stir it all up. I tend to use a wooden spoon for this, so that I can get in to the edges of the saucepan, and make sure it all gets incorporated. Don’t worry about any lumps at this stage. We can worry about those in good time later on.
Getting thicker. By adding the flour incrementally, we can be sure to get the right proportion (see my earlier comment about not measuring things!). By stirring it smooth after each addition, we also end up with a lovely smooth roux. A smooth roux is the key for a smooth sauce.
Add another slosh of milk, stir it in, and keep stirring while it thickens. This will take longer and longer each time you add the milk. Make sure you add small quantities at a time (it’s very tempting to add a lot, but it will slow the whole process down significantly, because you need to heat the whole lot again).
This is still a bit thin, but if you have a heavy-bottomed saucepan, it will continue to thicken as we go through the next few steps. The price you pay for a smooth sauce is eternal vigilance: you’ll only get lumps if you let it sit on the heat without stirring it. But, if you do have lumps at this stage, never fear! Add a little extra milk, and get your balloon whisk out. Give it a really vigorous beat to get the lumps out, and it should come good.