4 pounds mushrooms, preferably crimini
7 tbsp coarse salt
1 cup red wine vinegar
2/3 cup cider vinegar
1 medium red onion, finely chopped
1 clove garlic, finely chopped
1/2 tsp ground black pepper
1/2 tsp ground ginger
1/2 tsp ground allspice
1/2 tsp ground mace or nutmeg
Wipe mushrooms clean and chop coarsely on a large baking sheet
(with rim) lined with several layers of wax paper. Spread out and
sprinkle with salt.
Cover and refrigerate, stirring and squeezing with your hands
occasionally, for 2 to 3 days. Drain the mushrooms and rinse well,
discarding the liquid. Combine into a large nonreactive saucepan
with vinegars, onion, garlic and spices.
Bring to a boil, reduce the heat, and simmer, uncovered, stirring
often, until very fragrant and flavorful, about 30 minutes. Strain
into a clean saucepan, pressing out all the liquid. Bring to a
simmer, then strain through a dampened cloth. Can while hot, or
let cool, then cover and refrigerate for up to 1 month.