This one is a necessary one for any forager to have in their back pocket. You can really make an amazing mushroom stock one of two ways: keeping the water used to rehydrate dried mushrooms or taking fresh mushrooms and cooking them for a long time in water with other flavoring ingredients.
The liquid left from rehydrating mushrooms (and I’m specifically thinking morels here because that is the main mushroom I dry a lot of) is so delicious as a soup stock I cannot overstate it. It’s rich and filled with an earthy, umami depth of flavor with notes of just a touch of maple. It’s also extremely easy to make. I keep a quart size container in my freezer of this stuff and even when I’m only rehydrating a small amount of mushrooms, I take that liquid and dump it in the container. After a while, the container is full you’ve got a quart of amazing mushroom stock. You can take this liquid and boil it with some onion, garlic, leek, carrot, celery or whatever other vegetables you might like to add to round out its flavor, but it doesn’t need that either. It can go straight into a soup as is and perform miracles.
The second way I make a mushroom broth, is I just take mushroom trimmings or a variety of wild mushrooms (specifically maitake, chanterelles, hedgehogs, morels, oysters, or boletes all make great stocks) and cook them down in water with some other vegetables. I like to use the wild mushrooms that weren’t in great shape but were still okay to eat. You can use button, cremini or portobellos from the store too, if you like. Then put a stalk of celery in there, one onion, a few cloves of garlic and couple pinches of salt or soy sauce. Cover with water and either pressure cook, put it in a slow cooker, or simmer on stove top for a few hours. Remember, the fresh mushrooms have a lot of water in them, so it really takes some time to cook off that water and concentrate those flavors.
Once you have this stock, check out my mushroom udon soup or use it to make your very own mushroom risotto. Hope you like this stuff as much as I do!