Chop the mushrooms into small pieces and put them in a container with salt and bay leaves. Let it sit overnight.
Add chopped onion, zest of 1 lemon and grated horse radish to the mushrooms.
Add cloves, cayenne, allspice and cider vinegar to the mixture.
Stir all ingredients together and let it simmer for 15 minutes.
Allow it to cool and then pour it through a squeeze cloth to extract the liquid.
Save the liquid for future use and dry the leftover mushrooms.