You might think slimy, gooey or slippery foods unappetising, but Japanese seek out ingredients with such texture, which they call neba-neba. In this dish of cold soba noodles, neba-neba comes from fermented soybeans (natto), grated mountain yam (yamaimo or nagaimo), okra and poached egg (which you can leave out, if you want a vegan version).
Natto is a healthy, protein-rich ingredient sold in small packs in the refrigerated section of supermarkets. To increase the sticky character, stir the natto with chopsticks until you can see long strands when you lift the soybeans.
In restaurants, neba-neba soba is often drizzled with mentsuyu, a strong dipping sauce, either home-made or purchased (you’ll find it in bottles near the dried noodles). Most of these contain katsuobushi, or shavings of dried and fermented skipjack tuna, but vegetarian versions are also available. Be sure to check the ingredients label.
If you can’t find fresh wasabi (which is expensive) use grated ginger instead, because wasabi paste and powder are too strong.
Bring a large pot of water to the boil, add the soba and cook until firm-tender. Drain, rinse with cold water, then drain again. Put the noodles into a large bowl filled with iced water.
Bring a large pot of water to the boil, add the soba and cook until firm-tender. Drain, rinse with cold water, then drain again. Put the noodles into a large bowl filled with iced water.
Cut the okra pods on the diagonal into slices about 5mm (¼ in) thick.
Stir the natto until it forms long strands.
Peel the mountain yam, then grate it (preferably using a Japanese ceramic oroshigane) into a fine, sticky pulp. If using fresh wasabi, peel away just enough skin to expose what you’ll need for immediate use (the flesh darkens when exposed to air). Grate the wasabi, preferably on a sharkskin grater or ceramic oroshigane, until you have about 1½ teaspoons’ worth. If using ginger, peel it, then use the ceramic oroshigane to grate about 1½ teaspoons’ worth.
Bring a medium-sized pot of water to the boil, lower the heat to a low simmer, then stir in the white vinegar. Crack one egg into a small dish. Use a spoon to stir the water to create a vortex, then add the egg into the middle of the vortex. Continue to stir the water, taking care not to break the egg. Cook the egg for one minute, or until the white is softly set and the yolk is still runny, then use a slotted spoon to remove it from the water before placing it on a paper towel. Poach the remaining egg the same way.
Drain the soba noodles in a colander, shaking off the excess water. Divide the noodles between two plates or shallow bowls.
Divide the wakame, okra, natto, mountain yam and shredded nori between the plates, putting each ingredient in a separate pile. Divide the wasabi or ginger into two portions and shape each one into a small cone. Add one to the side of each plate.
Place a poached egg on top of the noodles, in the centre. Sprinkle with toasted sesame seeds, then serve the noodles with small bowls of mentsuyu.