In this month’s Japan Times food column, I write about the varieties of mushrooms available in Japan . It has a recipe for mushroom rice in there too - one of my favorite recipes for fall, for which I have a few variations (a couple of them are on this site, i.e. here  and here .
One of the things I talk about in the article is the mysterious mushroom-shaped clay objects that have been found from prehistoric excavation sites in northern Japan. Here’s a picture of some of these mushroom-shaped clay objects, pilfered from the Chiba Prefectural Museum  website. Aren’t they amazingly lifelike?
As I wrote in the article, they are generally thought to be made as visual aids to mushroom hunting - very lifelike models of edible mushrooms that people carried around in the forests, just like modern day mushroom hunters carry photographic field guides with them. It’s really fun to imagine people thousands of years ago packing up a selection of these clay mushrooms, perhaps with a basket and a little knife or something too, as they went foraging. I wonder how people in other regions tackled the problem of sticking to safe mushrooms in the days before illustrated manuals?
Whenever I go back to Japan, it really strikes me that while you can get basically any kind of fruit or vegetable, the ones that are inexpensive, and therefore most commonly used, differ a lot from the same in Europe (at least the parts I’m familiar with) or the U.S. Mushrooms are no exception. In Japan, shiitake, enoki, shimeji and maitake mushooms are quite inexpensive, while western button mushrooms are way more pricey. When I do a European style mushroom pasta with butter and garlic and wine and so on in Japan, I often use shimeji or maitake (shiitake have a too-specific aroma to me) instead of button mushrooms. (Matsutake  of course are in another strosphere.)
The selection of mushrooms here in southern France is very different of course. We can, in season, get the most gorgeous chantarelles or pleurotus (oyster mushrooms) and so on at pretty fair prices. And of course there are truffles  - very expensive still, but a lot cheaper than elsewhere. Here’s a mound of wild mushrooms being sold at a local market. A bear to clean, since they have bits of leaves and plenty of dirty in them, but so worth it.
This super-easy recipe can be made with a mixture of any kind of mushrooms you can get, even plain old button mushrooms, though the more wild-type mushrooms you can use the better. Baking times vary according to how big your mushrooms are, but range from around 20-30 minutes. In Japan I would use a mixture of fresh shiitake, shimeji and enoki, and here in France I’d use boletus, chantarelles and chestnut mushrooms if I can.
Preheat the oven to 180°C / 360°F.
For each serving, use a good big handful of cleaned mushrooms. If the mushrooms are very large or thick (e.g. if you’re using trumpet mushrooms or eringi*), slice them lengthwise or shred them. Small or thin mushrooms can be used whole.
Spread the mushrooms out on a piece of foil or ovenproof parchment paper. Sprinkle with about 1 tablespoon of sake and 1 to 2 tablespoons of soy sauce. (If you can’t use sake, leave it out, though you will miss out a bit on taste.) You can also add a little grated ginger if you like.
Fold the foil over and seal the edges well. Put the foil packets in the oven on a baking sheet an bake for around 20 to 30 minute, depending on the size of your mushrooms.
Open the foil carefully since it will be very hot! Serve with some kaposu or sudachi wedges, if you’re in Japan (or can get a hold of these Japanese citrus fruits) or lemon or lime wedges. To make it richer, add a pat of butter to the still-hot mushrooms. Eat with plain rice, mixed into buttered pasta.
[*I am not a big fan of eringi or trumpet mushrooms. They have even less flavor to me than button mushrooms. They are a very recent introduction to Japan by the way, having only been available there since the ’90s, and they are inexplicably popular…perhaps because they look so impressive.]