Spinatch with mustard soy sauce ほうれん草の芥子醤油
In general, fruits and vegetables are much tastier and better in Japan with few exceptions. These exceptions include carrots and spinach. Carrots available in the U.S. are thinner, longer and much sweeter especially when eaten raw. Western varietals of spinach are tender and good for eating as a salad especially "baby" spinach. Although Western varietals of carrot and spinach are now available in Japan, traditional Japanese spinach is rather tough and not suited to eating raw as salad and contain a high amount of oxalic acid. I still remember that my mother told me when I was a child that spinach had to be boiled in a large amount of water and then soaked in cold water to remove as much oxalic acid as possible. I am not sure common Western varietals have a significantly lower oxalic acid content, however. It is getting difficult to find bunches of fully grown spinach in our grocery stores. Instead, I often end up with pre-washed and packaged "baby" spinach. I think that, for traditional Japanese ways of preparing spinach like seen here, it may be better with bunches of Japanese or Asian spinach since Western spinach does not have a same texture.
I prepared two rather common sauces to serve with spinach. One to the left is with black sesame sauce as described in Mark's book p76. One to the right is dressed with a mustard soy sauce or "karashi jouyu" 芥子醤油 and topped with dried bonito flakes. I cooked the whole bag of baby spinach (which yielded only two servings) in a small amount of water in a sauté pan with a tight-fitting lid for 2 minutes or until the spinach wilted. I drained and let it cool. I squeezed out any extra moisture and rolled it using a Nori sheet in a long cylindrical shape like making a roll sushi. I left it wrapped in plastic wrap until the Nori absorbed the moisture and adhered to the spinach (few minutes). I then cut the the roll into 1/2 inch pieces yielding 8 pieces.
Both are good, although we really liked the black sesame sauce. Toasting the sesame seeds really brings out the nice fresh fragrant flavor of sesame. Black sesame paste adds a nice nuttiness. I had to find "adult" (as opposed to "baby") spinach for this dish, though.