Cold Miso Soup (Hiyajiru)

1. Gather all the ingredients.

To Make the Dashi (Japanese Soup Stock)

1. First, make the dashi. Add 2½ cups water and 1 dashi packet to a saucepan, and bring it to a simmer on medium heat. Let it steep for 2–3 minutes on medium-low heat. Remove from the heat and let the saucepan cool over a bowl of iced water. For vegans/vegetarians, you can make Kombu Dashi.

To Prepare the Sesame and Miso

1. On a baking sheet lined with aluminum foil, spread 4 Tbsp miso.
2. Toast the miso in a toaster oven or the oven broiler for several minutes (8 minutes for my toaster oven) until the surface is slightly charred. Remove from the toaster/broiler and let cool.
3. Add 2 Tbsp toasted white sesame seeds to a Japanese mortar, reserving some sesame seeds for garnish later. Using a Japanese wooden pestle, grind the sesame seeds.
4. Add the toasted miso to the mortar and set it aside (we‘ll mix them with the chilled dashi later).

To Prepare the Ingredients

1. Peel the skin of 4 oz Japanese or Persian cucumber in stripes by alternating peeled and unpeeled strips down the length of the cucumber. Then, thinly slice it.
2. Transfer the cucumber slices to a tray or plate and sprinkle with ¼ tsp Diamond Crystal kosher salt. Gently rub the cucumber slices with your hands. The salt will draw out the moisture from the cucumber slices and make them crisp. Set aside for 5 minutes.
3. Remove the stems of 10 shiso leaves (perilla/ooba) and roll them up. Cut them into julienned strips. Set aside.
4. Break up 1 fillet cooked salmon into smaller pieces. Squeeze the cucumber slices to remove the moisture. Keep all the ingredients on a tray or plate.

To Assemble and Serve the Soup

1. When the dashi is cold and the toasted miso is no longer hot, pour a small portion of the dashi into the mortar. Using a silicone spatula or spoon, stir well to dissolve the miso in the stock.
2. Once the miso is dissolved completely, add the rest of the dashi and mix it all together.
3. Cube 7 oz medium-firm tofu (momen dofu) (the Japanese usually cut tofu while holding it on their palm, but you can cut it into ½-inch (1.3 cm) cubes on a cutting board first). Add the cubed tofu to the mortar. Then, add the salmon pieces.
4. Add the cucumber and shiso leaves. You can chill the soup longer in the refrigerator or you can serve it immediately in individual bowls. Typically, Cold Miso Soup is served with steamed rice. Some enjoy it by pouring the soup over rice or vice versa.

To Store

1. You can keep the leftovers in an airtight container for 2–3 days. You do not need to reheat. Enjoy it chilled.