Sos beszamelowy zaciągany serem i żółtkiem - przepis naszych pradziadków

A sauce based on a 100-year-old recipe. Velvety and very tasty: 1 heaping tablespoon of all-purpose flour 1 heaping tablespoon of butter 1 to 1 1/2 cups of milk 3 tablespoons of grated hard cheese 2 beaten egg yolks a pinch of salt 1/3 teaspoon of ground white pepper