John Cage once read in a book that “catsup” is a thin liquid. So, as he likes it thick, he calls his recipe “dogsup.” This can be done with any kind of edible mushroom and must be kept at least a year before being used.
Break the mushroom caps in small bits; slice the stem. Place in an earthenware jar with 1 tablespoon of salt for each pound of mushrooms. Let stand in a cool place for 3 days, stirring and mashing several times a day. On the third day, put over a low fire, in an enamel or Pyrex pan, until the juices flow freely. This takes about ½ hour. At that moment, a “catsup” is strained through a sieve; the “dogsup” is just mashed. Simmer for 20 more minutes. Measure the mash, add to each half pint: 1 ounce ginger root, chopped or grated; a blade of mace; a bay leaf, broken up; a pinch of cayenne; 1 ounce each of black pepper and allspice. Boil down to half the quantity. Add, for each half pint, a teaspoon of the best brandy. Bottle, cork, and seal.