Choose three bunches of the most beautiful asparagus from large young Dutch plants, that is to say white ones with purple tips. Trim them, wash and cook them in the ordinary way, that is to say by plunging them in boiling water. Slice them afterwards by cutting them on the bias near the tip into pieces the length of the little finger. Use only the best parts, setting aside the rest of the stems. Put the chosen pieces in a hot napkin so as to drain them and keep them hot while you prepare your sauce.
Empty a medium-size pot of butter from Vanvre or Prévalais and put the contents in spoonfuls in a silver dish. Add a few grains of salt, a good pinch of powdered mace and a generous spoonful of pure wheat flour; and in addition the yolks of two fresh eggs diluted with four spoonfuls of the juice of sour Muscat grapes. Cook this sauce in a double boiler; do not allow it to thicken excessively and thus become too heavy. Put your sliced pieces of asparagus in the sauce and serve it all in a covered casserole as an extra, so that this excellent course does not languish on the table and can be appreciated at the height of its perfection.