Prepare the mushrooms: Gently wipe any dirt off the mushrooms with a damp paper towel. Trim them as needed: for shiitake, discard stems and cut caps into wedges; for oyster, trim tough stem ends and cut large caps into 1½-inch pieces; for hon-shimeji, trim the base and separate into smaller clusters.
Temper the spices: Heat the oil in a medium nonstick pan over medium-high heat.
Once hot, add the mustard seeds.
When they start to pop, add the cumin seeds and let them sizzle for a few seconds. Carefully add the crushed curry leaves—they will splutter.
Sauté the aromatics: Immediately add the chopped shallots, green chili, and garlic to the pan.
Sauté, stirring frequently, for about 3 minutes until softened and fragrant.
Cook the mushrooms: Add all the prepared mushrooms and ¼ teaspoon of salt to the pan. The pan will seem full, but the mushrooms will cook down.
Stir gently for about 4 minutes until they release their moisture.
Stir in the ground coriander, chili powder, and turmeric, and cook for another 2 minutes.
Create the sauce: Pour in the coconut milk and bring the stew to a gentle simmer.
Cook for 2 minutes to allow the flavors to meld.
Remove from heat, stir in the fresh lime juice, and taste.
Adjust salt and seasonings as needed before serving.
Don't be afraid to mix your mushrooms! If you can't find the specific varieties listed, feel free to substitute with cremini, portobello, or any other flavorful mushroom you love.