In a medium pot, combine 3 cups of dashi, 2 tablespoons of sake, 1 tablespoon of soy sauce, and ¼ teaspoon of salt. Bring the mixture to a boil over medium-high heat, stirring occasionally.

Once the broth is boiling, add 150 grams of chopped napa cabbage, the white parts of the scallions, and 50 grams of sliced shiitake mushrooms. Reduce the heat to medium and let it simmer for 10-12 minutes.

While the broth is simmering, bring a large pot of water to a rolling boil. Carefully add 12 gyoza dumplings and stir gently. After 1 minute, transfer them into the soup.

Let the dumplings simmer in the broth for an additional 2-3 minutes, allowing the flavors to meld.

Remove from heat and stir in 30 grams of sliced scallions and 1 teaspoon of toasted sesame oil. Serve hot, garnishing with extra scallions if desired.