Kitsune Udon — Japanese Sweet Tofu-Pouch Udon Soup

Without wiping off the white powder on the kombu (it adds flavor), place it in 700 ml cold water and heat slowly over low heat. When tiny bubbles appear around the edges, at about 60–70°C / 140–158°F, remove the kombu. Bring the water to a boil, turn off the heat, add the katsuobushi flakes, and wait 2 minutes for them to sink. Strain through a fine-mesh sieve without pressing.

In a small saucepan, bring 150 ml water, 15 ml soy sauce, and 15 g sugar to a boil, then arrange the pouches in a single layer. Cover with a small plate or a piece of cut parchment paper and simmer over low heat until almost all the liquid has evaporated. The pouches should darken and be full enough to release sauce when squeezed.

Place the drained udon in warm bowls first, then pour in enough soup to cover the noodles. Set the sweet tofu pouches in the center and scatter thinly sliced scallions alongside. Serve the shichimi togarashi separately so everyone can add it to their own bowl at the table.