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

Reduce the heat to medium and add 150g of sliced napa cabbage and 50g of sliced shiitake mushrooms. Simmer for 10 to 12 minutes, stirring occasionally.

In a separate pot, bring water to a boil and add 12 gyoza dumplings. After 1 minute, transfer them into the simmering soup.

Combine the gyoza with the soup and cook for an additional 2 to 3 minutes.

Stir in 30g of sliced scallions and 1 teaspoon of toasted sesame oil just before serving.

Serve hot alongside steamed rice or a cucumber salad.