Remove the pit from the umeboshi and mince the flesh. Finely chop the green onion (or shiso leaves).
Grate the nagaimo or roughly mince in a food processor without blending it too smooth.
Combine the ＊ condiments and chill.
Cook the pasta with liberally salted water. Drain and chill under running water.
Toss the pasta, umeboshi, green onion, and ham with the sauce from Step 3. Dish it up.
Pour the nagaimo over the pasta. Top with nori and sesame seeds if available.
In this photo, I added pickled cucumbers and eggplants, umeboshi, cured ham, marinated tomato, and sesame seeds. I've added lots of shiso leaves as well.
You can mix anything into this delicious pasta dish.
Story Behind this Recipe
I used to make a warm nagaimo spaghetti dish. I prepared it chilled for a change, and it still tasted amazing.
Take care not to overcook the pasta. Since the nagaimo is unseasoned, make the sauce in Step 3 on the salty side, like store-bought mentsuyu. It's best eaten with plenty of sauce that there'll be leftovers.