How to Make Béchamel Sauce

50g butter
1 heaping tablespoon all-purpose flour
250ml hot milk (300ml for a thinner sauce)
salt
pepper
nutmeg (optional)

1. Melt the butter over low heat in a small saucepan.
2. Add the flour and whisk well until you get a smooth paste, then cook for another minute to lightly toast the flour, stirring constantly.
3. Start adding the milk slowly... like making mayonnaise. At the same time, whisk the sauce. Continue the same way: pour a little milk, incorporate with the whisk, more milk, whisk again, until all the milk is added (work with both hands - pour the milk with one hand while whisking with the other).
   * When you've added all the milk, if the sauce is thicker than desired, you can add a bit more hot milk.
4. Let the sauce simmer for another minute while stirring constantly.
5. Season with salt, pepper, and optionally a little nutmeg.