I use a 2x concentrate mentsuyu sauce, but dilute it with 3 times the amount of water.
Cut the kamaboko slice into half lengthwise.
Slice it into 3 thin slices.
Stack up the slices and cut in to 2-3 mm thick strips.
Slice the onion very thinly.
Wash the leeks and slice on the diagonal into 5-6 cm wide pieces.
This is for 3 servings, but from this point on each serving will be made separately so divide all the ingredients into 3 equal portions. Break 1 egg into a bowl and beat it up.
Make 1 portion at a time. Put 1/3 of the prepared sauce into a small, shallow pan. Cook over high heat and add the onion. When it comes to a boil lower the heat to medium.
Simmer for 3 minutes over medium heat, then add the kamaboko.
Add the leek after 1 minute.
After another minute turn the heat back up to high and add the egg. When the egg is soft-set turn the heat off. Put some rice into a bowl and put the egg mixture on top. Sprinkle with some sansho pepper to finish. Make the rest of the servings in the same way. Top with shredded nori seaweed to taste.
Story Behind this Recipe
I was chosen to become a tester for a certain bottled mentsuyu noodle sauce brand. It was so delicious that I tried it in a donburi rice ball recipe that I make all the time, and it improved and rounded out the flavor quite a bit. Of course you can make this with any mentsuyu sauce.