Wild World Foraging
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From the Wisconsin woods to the smoker

Smoked Elm Oyster Soup

A wild mushroom soup built on mushroom stock, a pale shallot-and-leek mirepoix, Korean doenjang and fruity Peruvian ají amarillo.

Hypsizygus ulmarius growing from a mossy tree
Hypsizygus ulmarius in the wild. Photo: Wild World Foraging.
Yield4 servings
Prep20 minutes
Cook45 minutes + smoking
Smoke225°F / 107°C

The common name “elm oyster” can be a little misleading. Here in Wisconsin, every Hypsizygus ulmarius I’ve personally found has been growing on box elder — never elm. This recipe takes that substantial wild mushroom and gives it a trip through smoke, Korean fermentation and Peruvian chile.

The idea is to smoke the caps gill-side up, allowing their natural bowl shape to catch some of the moisture they release. If that liquid collects, it becomes part of the broth rather than something we lose to the smoker.

Smoke. Earthiness. Fermentation. Fruity heat. Bright acidity.
Harvested elm oyster mushrooms showing their pale gills
The pale gills and substantial structure of harvested Hypsizygus ulmarius.

Method

Smoke the mushrooms

Preheat the smoker to 225°F / 107°C. Clean and trim the mushrooms, but do not oil or season them. Arrange them gill-side up on a sheet pan lined with a silicone mat, positioning the caps like shallow bowls. Begin checking at 30 minutes and remove when tender and noticeably smoky but still succulent. Carefully reserve any liquid collected in the caps.

Build the white mirepoix

Melt the butter over medium-low heat. Add shallots, celery and leek with a small pinch of salt. Sweat for 8–10 minutes without browning. Add garlic and ginger and cook for another minute.

Build the broth

Add the mushroom stock and bring to a gentle simmer. In a small bowl, loosen the doenjang with a ladleful of hot broth, then stir it back into the pot. Add the ají amarillo. Start conservatively; its fruitiness should brighten the smoke and fermentation, not dominate them.

Bring it together

Reserve several attractive mushroom pieces for garnish. Chop the rest and add them to the soup along with any juices captured during smoking. Simmer gently for 10–15 minutes. Taste before adding soy sauce—the doenjang may already provide enough salt and umami.

Finish

Stir in the rice vinegar. Adjust seasoning. Divide among warm bowls and finish with the reserved smoked mushrooms, sliced scallions, toasted sesame seeds and only a few drops of toasted sesame oil.

Finished smoked elm oyster soup with doenjang, ají amarillo, leek and black sesame
The finished smoked elm oyster, doenjang & ají amarillo soup.
EarthySmokyFermentedFruity HeatBright

Field Note

Never identify a wild mushroom from a single characteristic. Confirm the host and growth habit along with cap, gills, stem, spore print and appropriate regional identification features. Only eat a wild mushroom when you are confident in its identification.

Testing Notes

This is the tested version of the recipe. The cook worked quite well, with two changes from the original draft: leek replaced parsnip in the mirepoix, and the mushrooms went into the smoker completely unseasoned on a silicone-lined sheet pan. The rest of the method remains the same.