Cut a blanched throat sweetbread (No. 601) into small pieces, and put them into a saucepan, with half an ounce of good butter, six mushrooms, and one truffle, all nicely cut into dice-shape. Thicken with half a pint of good bechamel sauce (No. 154), or Allemande sauce (No. 210), and let cook on a slow fire for five minutes, gently tossing mean-while. Finish by adding half an ounce of crawfish-butter (No. 150); stir well, and it will then be ready to use for the desired garnishing.