Niku Udon

In a medium saucepan, combine 6 cups of water and the piece of kombu. Place over medium-high heat.

Bring the water just to a simmer, then immediately remove the kombu. Do not let it boil.

Add the katsuobushi (dried bonito flakes) to the saucepan. Bring to a gentle simmer, then turn off the heat.

Let the katsuobushi steep in the hot water for about 5-10 minutes, or until the flakes sink to the bottom. Do not boil.

Strain the dashi through a fine-mesh sieve into a clean bowl or pot. Discard the solids.

In a skillet, combine the thinly sliced beef, sliced onion, sliced scallion whites, sugar, soy sauce, mirin, and sake.

Cook over medium heat, stirring occasionally, until the beef is cooked through and the onions are tender, about 5-7 minutes. The beef will shred and break apart as it cooks.

Bring a large pot of unsalted water to a rolling boil.

Add the udon noodles to the boiling water and cook according to package directions, usually 3-5 minutes for fresh or frozen noodles. They should be tender but still have a slight chew.

Drain the noodles well in a colander.

Gently reheat the strained dashi broth in a saucepan. Taste and adjust seasoning with more soy sauce or mirin if desired.

Divide the cooked udon noodles among serving bowls. Top with the beef and onion mixture.

Ladle the hot dashi broth over the noodles and beef.

Garnish with sliced scallion greens and a sprinkle of shichimi togarashi, if desired.