Bathed in an icy shiro dashi soup broth, this Cold Somen Noodles with Sudachi Lime is a refreshing treat on a hot summer day. The light color of this savory and tart broth brings out the vibrant green and yellow hues of the citrus slices for a cooling and beautiful presentation.
Thinly slice all the sudachi or limes except for one (for 2 servings) and set aside for garnish. Cut the remaining sudachi or lime in half widthwise and reserve for juicing.
To Prepare the Shiro Dashi Soup Broth
To make 2 servings, you will need roughly 400 ml of ice-cold shiro dashi soup broth. If you are using Homemade Shiro Dashi, combine 300 ml of the homemade shiro dashi and 100 g of ice cubes (NOT iced water). Tip: my homemade shiro dashi is not as concentrated as a store-bought one.
If you're using store-bought shiro dashi, combine 80 ml of this concentrated shiro dashi and 320 ml of iced water including several ice cubes for 2 servings. Once you have added either ice cubes or iced water to your shiro dashi base, squeeze the sudachi or lime halves and add the juice to your prepared shiro dashi broth. Mix it all together. Tip: Each brand of shiro dashi has different saltiness, so please adjust to your liking.
To Cook the Somen Noodles
Bring a large pot of water to a boil. (You do not need to add salt to the water.) Meanwhile, remove all the wrappings from the bundles of somen, as all the noodles should go into the boiling water at the same time. Tip: Somen noodles cook very fast, so it's important to work quickly. When the water is boiling, add the somen all at once, spreading the noodles around the pot in a circular motion to separate each strand (I use a motion similar to opening a Japanese folding fan).
Cook in the boiling water, stirring occasionally with chopsticks, for 1 to 1½ minutes or according to the package instructions. If it looks like the water may boil over, add a small amount of cold water to the pot. When the noodles are done, drain them in a colander. Tip: I slightly undercook my noodles to keep their springy texture.
Rinse the somen under cold running water. Once the noodles are cool enough to handle, rinse them with your hands as if you are washing your clothes. Knead and massage the noodles to get rid of the excess oil.
To Assemble and Serve
Serve the cold somen noodles in individual bowls and optionally add several ice cubes to the bowls. Add enough soup broth to the bowls to reach halfway up the noodles. Depending on the size and shape of your bowls, you may need to make more broth.
Garnish on top with the thinly sliced sudachi and serve immediately.
You can keep the leftovers in an airtight container and store in the refrigerator for up to 2 days. If the noodles stick to each other under refrigeration, run them under cold water to loosen them up before serving. Ideally, you should boil the noodles right before serving so they won't lose their perfectly springy texture.