Gather all the ingredients.
If you are going to/need to make Mentsuyu from scratch, follow the recipe here.
Bring a large pot of water to boil for udon noodles. My favorite udon is the frozen Sanuki Udon. Cook the frozen udon noodles in boiling water for 1 minute (no need to defrost). If you use dry noodles, follow the package instructions. Remove udon from boiling water and cool in an ice bath. Wait until it cools completely and drain.
Recipe by Namiko Chen of Just One Cookbook. All images and content on this site are copyright protected. Please do not use my images without my permission. If you’d like to share this recipe on your site, please re-write the recipe and link to this post as the original source. Thank you.