Prepare the toppings: Prepare tenkasu in a small bowl. Place the dried wakame in a small bowl and let it soak for about 5 minutes. Drain the seaweed completely. Finely chop the scallion.
Make the Udon Soup: In a large pot, add water, dashi powder, mirin, soy sauce, and salt and boil over medium heat.
Boil the Udon Noodles: While making the soup, add the udon noodles to a separate pot of boiling water and cook them for about two minutes.
Drain the noodles: Drain using a strainer and quickly rinse under cold water to remove the extra starch.
Serve: Serve the drained noodles in a bowl, pour the soup, and place the tenkasu, wakame, and scallions on top. You can top it with shichimi togarashi, a Japanese spice, for an extra kick.
Notes
Adjusting Soup Seasoning: If your udon soup is too salty, you can balance it by diluting it with water. Conversely, if it's too mild, add more salt to enhance the flavor.
Udon noodle cooking time typically takes a couple of minutes to cook frozen udon noodles and around 10 minutes or more for fresh or dried udon noodles. The cooking time can vary depending on the type and brand of udon noodles, so please follow the package directions.
Making homemade tenkasu is simple. Prepare a tempura batter, apply a generous amount to a brush, and gradually drop it into hot oil. Fry for about 2 minutes or until golden brown.