Japanese Mountain Yams in Amazake Beurre Monté
With Pine Nut Miso

My first time eating Japanese mountain yams was on our honeymoon in California, at an incredible izakaya called Ippuku, in Berkeley. By the time the dish reached our table, I knew I was in for a unique treat. White cubes, lightly grilled, and finished with a delightfully umami flakey sea salt. It was so simple, and it was so good. The outside of the yam skin had texture, while the inside was airy, like popcorn. I remember thinking that I had never had anything like it before. It wasn't that it was the greatest tasting vegetable I had ever had; rather it’s simplicity and austerity encapsulated what I love and respect about the Japanese attitude towards food. 

Recently I found Japanese mountain yams for sale at my local Asian grocery store. I had bought them accidentally, thinking they were burdock roots. Happy to be reunited with this ingredient, I lightly grilled and sprinkled them with my fermented persimmon salt. Very delicious, about as good as they were when I first ate them.

I decided then to take a more maximalist approach to cooking them. Now they’re served two ways: grilled, as they had been, and grated into a slurry. With a little research, I learned that one of the most popular ways of eating Japanese mountain yams in Japan is to grate them into a slurry. I say slurry because these yams are incredibly slimy and slick. Once grated, they can be used to thicken a soup or add texture to rice.

Next I decided to make a sauce. I had in my fridge the beginnings of a great soup, or a great mixed drink, depending on how you’re feeling. It was my homemade amazake, something between a rice wine and a rice vinegar made from koji  (aspergilus oryzae mold grown on rice), mixed with a bit of whiskey and mint. I threw it in a pan and made myself some beurre monté, a simple butter emulsion sauce.

When I plated the sauce and grilled yams, I noticed how the bowl looked a bit lonely, a bit boring. I added a dollop of pine nut miso and garnished with fresh mint, and the dish was done.

I started the batch of pine nut miso around the time I bought Koji Alchemy, about two months ago. Following their instructions, I used my protein of choice, pine nuts, which I toasted and mixed with koji and salt. The flavor has really taken me by surprise. It’s almost sweet, like nutmeg, while also tasting umami, like cheddar cheese.

Thinking back, having made this dish as a literal snack after work, I had absolutely no idea what it would taste like. Turns out, it tastes pretty damn good. The super malty flavors from the whiskey pair with the mint quite well, while the miso lends a nutty undertone and the persimmon shoyu hits your mouth with umami richness. In all seriousness the combined flavors reminded me of mint chocolate, though less sweet and more savory. The yam, almost flavorless on its own, took on all the flavors quite nicely. I wouldn’t eat this every day, but I can think of some adventurous foodie friends of mine who would enjoy the adventure of flavor that is this dish. 

For the amazake beurre monté:

• 1/4 cup sour amazake
• A splash of whiskey (I used Wild Turkey)
• 2-3 fresh mint leaves, plus more to garnish
• Butter, cubed

For the Japanese Mountain Yams:

• 1 7-inch mountain yam, peeled and cubed
• Persimmon salt, to garnish
• 1 3-inch mountain yam, peeled and grated
• A splash of persimmon shoyu

For the pine nut miso:

• 250g pine nuts, roasted
• 250g koji
• 25g salt

To make the pine nut miso: Toast pine nuts in a pan or in the oven until golden brown. Allow them to cool to body temperature. Meanwhile, add the koji and salt to a food processor and pulse a few times. When the pine nuts are cool, add those to the food processor and process until homogenized. Transfer the mixture to a sterilized container. Press out as much air as you can manage. Sprinkle additional salt on top of the miso. Press a weight down on the miso; I use a Ziplock bag filled with salt. Screw a lid on the jar and wait patiently, at least four weeks. Check your miso from time to time, keeping an eye out for unwanted mold. Over time, the fragrance and flavor of the miso will develop its umami complexity. Enjoy the process and feel free to taste as it goes.

To make the amazake beurre monté: In a small sauce-pan, warm the amazake over medium-high heat. When it reaches a simmer, add a splash of whiskey and some mint leaves. Return to a simmer and allow the the mixture to reduce and alcohol to burn off, about 10 minutes. If you have roughly more than 2 tablespoons of amazake mixture left in the pan, might I suggest drinking the excess? You’ll want to try it—and besides, you don’t want a ton of liquid for making beurre monté.

Have your cubed butter and whisk at the ready. Working with one piece of butter at a time, place a cube of butter into the pan with the simmering amazake mixture and whisk in a circle continuously, until dissolved. Continue adding cubes of butter, one at a time, until your emulsified butter sauce is thick enough to coat the back of a spoon. This can take up to 10 or 15 minutes, depending on the amount of amazake mixture you started with. 

If you are preparing to serve the dish right away, then leave the sauce on the burner with the heat turned down to its bare minimum in order to keep it residually warm. Otherwise you can store it in a container in your fridge and use it like seasoned butter. Be warned: the beurre monté will break if you attempt to reheat it right away.

To make the Japanese Mountain Yams: Preheat a grill to 375F and get some bamboo skewers soaking in water. Meanwhile, peel the skin off of the yams. Handle carefully; they will slip out of your hands. Take the larger yam and cut it into 1 1/2-inch cubes. Skewer and set aside. Take the smaller yam and grate it with a microplane over a bowl. When the yam is sufficiently grated into a slurry, splash some persimmon shoyu in the bowl and lightly mix. Set aside.

Grill the skewered yams lightly on 2 or 3 sides for 5 minutes at a time. A little color is okay but we’re not looking for serious char. Remove from the heat and set aside.

To plate, pour some amazake beurre monté into a bowl. Follow with cubes of yam. Place a spoonful of yam slurry in the beurre monté, to one side of the grilled cubed yam. Place a dollop of pine nut miso to the other side of the grilled yam. Sprinkle persimmon salt over the cubed yams. Garnish the bowl with mint leaves. Serve warm.