This is a test of commonsense. Complete the next sentence:

How to make bechamel sauce
This is the basic recipe for bechamel sauce.
Place 2 tablespoons of butter in a small saucepan.
Heat the butter over medium heat until it's melted.
Always keep the ratio of butter to flour equal, regardless of whether you are producing a thinner or thicker sauce. Mix in 2 tablespoons of flour to make a roux, or the beginning stage of the sauce.