Whether served on top of a bowl of rice or with chewy udon noodles, thinly shaved beef cooked with onions in a sweet-savory dashi broth is classic, warming Japanese comfort food that can be made in minutes once your pantry is stocked with a few simple Japanese staples.

Ingredients

For the Dashi (see Tips)

• 20 grams/about 2 (4-inch) squares kombu
• 20 grams/about 2 cups loosely packed katsuobushi (dried bonito flakes)

For the Beef

• 1 pound thinly shaved beef (see Tips)
• 1 small yellow onion, thinly sliced\
• 1 bunch scallions, white parts cut into 2-inch segments and halved lengthwise, light green parts thinly sliced at a sharp angle
• 1 tablespoon granulated sugar
• ¼ cup sake
• 2 tablespoons soy sauce
• 2 tablespoons mirin

For Serving

• 2 tablespoons soy sauce, plus more as needed
• 3 tablespoons mirin, plus more as needed
• 1 pound fresh or frozen udon noodles
• Shichimi or nanami togarashi, or use your favorite chile powder (optional)

Instructions

1. Make the dashi: Combine 2 quarts cold water and the kombu in a medium saucepan, and place over medium heat. As soon as the water boils, remove from heat and add the katsuobushi, pushing it gently into the water to submerge (don’t stir vigorously). Steep for 5 to 10 minutes. Strain and discard the kombu and katsuobushi (or reserve to make another batch of weaker dashi) and return the dashi to the saucepan. Keep warm, but don’t let it boil.