Stuffed Shiitake Mushrooms with Walnut Miso

It's still hot enough here to sweat through a shirt, but the grocery stores have already moved on. They're piled high with sweet potatoes, freshly harvested rice, and mushrooms. School's started too, and between the two of them I can almost imagine a cool autumn breeze coming in. These stuffed shiitake mushrooms are my way of taking a shortcut to fall.

The thick meaty shiitake caps are stuffed with kurumi miso, a Shinshu specialty. Nagano grows more than half of Japan's walnuts, and this savory condiment shows up throughout the regional repertoire. Loosened with soba noodle boiling water, it makes for a delightful dipping sauce, or spread some over gohei mochi, the flattened rice cakes grilled on skewers in the Kiso and Ina valleys. In my version I use honey to bring the balancing sweetness, and a floral pop that plays off the toasted nuts and salty red miso.

To enhance their nutty flavor, I like to pan-roast the walnuts in sesame oil over relatively low heat until they're golden brown and start smelling like popcorn and caramel. Take your time here as it's what develops the earthy character of this rustic condiment. I also add a bit of chili pepper to liven it up, and I used part of a Japanese green chili (ao-togarashi), but part of a jalapeno or a dash of shichimi togarashi would work just fine.

For the shiitake mushrooms, I recommend looking for the biggest, thickest caps you can find. Mine ran about three inches across and three-quarters of an inch thick through the middle. Small portobellos or any mushroom with a thick cap that's big enough to hold the walnut miso will work.

This recipe will make more walnut miso than you need for 6 mushrooms, but it keeps for weeks in the fridge, and works its magic on celery, cucumber boats, peppers. It's also the perfect filling for onigiri or a bowl of steaming hot rice.