Hiyashijiru (Chilled Cucumber and Shiso Soup)
On a hot, humid day, try this Japanese chilled soup for a refreshing, light meal.
1 pound Pickling Cucumbers
1/2 teaspoon salt
1/4 cup white sesame seeds
1 cup vegetable broth
3 tablespoons white miso
2 teaspoons granulated sugar
3 large leaves green shiso, finely julienned
4 hot servings cooked white rice
Cut the ends off your cucumbers and use a mandoline (or really good knife skills!) to slice them into thin slices, around 1/16" thick. When this is done, toss the cucumbers with the salt and let them sit, covered, on the counter for at least a half an hour. (This is a very important step, because the salt will draw out the water from the cucumbers, giving them their crunchy texture in the soup. It's the same principle behind salting cucumbers before pickling.)
After the half hour is up, or when your cucumbers have turned translucent (whichever is first,) pick up small handfuls of cucumber and squeeze them until no more water comes out. Then, turn the ball of cucumber in your hand and squeeze again, repeating until the cucumbers have no more water in them. Place these squeezed cucumbers into a clean bowl. Do this with all the cucumbers. (You'll notice that you lose a LOT of water from the cucumbers as you work. This is normal. If you started with a pound of cucumbers, you should have about 8 ounces of cucumbers by this point, or a little less. That's normal!)
That was the most labor intensive part of the process. Making the broth is easy in comparison. Start by putting your sesame seeds in a food processor and processing them until they have the consistency of wet sand. After that, add the vegetable broth, miso, and sugar and blend altogether until smooth, around a minute and a half.
Pour the sesame broth over the cucumbers and stir to combine, evenly coating the cucumbers. Add the julienned shiso next, stirring again to incorporate. Cover and let chill in the fridge until ready to use.
When you're ready to serve, put one serving of piping hot rice into a bowl. Carefully ladle the soup over the rice. If you like a little heat in your soup, sprinkle a little bit of crushed red pepper on top. Serve as soon as the soup has been poured over the rice.