This sauce resembles the famous French Bechamel Sauce, but it is simpler in its composition.
Put the flour and butter in a saucepan. Stir the flour and the butter together while keeping them over the fire. When the flour begins to be browned, pour over the milk, continually stirring with a wooden spoon until you see the liquid condensed like a cream. This is the Balsamella. If it is too thick add some milk, if too liquid put back on the fire with another piece of butter dipped in flour.
A good Balsamella and some well prepared brown stock are the base and the principal secret of many savory dishes.