Take small fresh-gathered button mushrooms, peel them carefully
with a penknife, and cut off the stems; throwing the mushrooms
into salt and water as you do them. Then put them into a porcelain
skillet of fresh water, cover it closely, and set it over a quick
fire. Boil it as fast as possible for seven or eight minutes, not
more. Take out the mushrooms, drain them, and spread them on a
clean board, with the bottom or hollow side of each mushroom
turned downwards. Do this as quickly as possible, and immediately,
while they are hot, sprinkle them over with salt. When they are
cold, put them into a glass jar with slight layers of mace and
sliced ginger. Fill up the jar with cold distilled or white wine
vinegar. Put a spoonful of sweet oil on the top of each jar, and
cork it closely.