Place the finely chopped napa cabbage in a bowl, sprinkle with 1/4 tsp salt, toss and let sit 10 minutes. Squeeze out excess moisture using a clean kitchen towel or paper towels until mostly dry. This prevents soggy filling.

Make filling

In a large bowl combine ground pork, squeezed cabbage, green onions, minced garlic, grated ginger, 1 tablespoon soy sauce, 1 teaspoon sesame oil, 1/2 teaspoon salt, and 1/4 teaspoon white pepper. Mix thoroughly until well combined and slightly sticky (use a spatula or your clean hands).

Assemble gyoza

Place a gyoza wrapper on your palm. Dab about 1 teaspoon of water around the edge to moisten. Put about 1 tablespoon of filling in the center of the wrapper (adjust to wrapper size). Fold wrapper in half over filling to form a half-moon and pleat the edge to seal (make 5–7 pleats) or simply press firmly to seal. Place finished gyoza on a lightly floured tray seam-side up. Repeat until filling is used (about 36 dumplings). Keep covered with a damp towel to prevent drying.

Steaming & plating

Prepare steamer

Fill a wide pot with about 3–4 cups of water (enough to steam for 6–8 minutes without touching the gyoza). Bring water to a simmer over medium heat. If using a bamboo or metal steamer, line the steamer basket with parchment paper with holes punched, cabbage leaf, or brush lightly with neutral oil to prevent sticking.

Steam gyoza

Arrange gyoza in a single layer in the steamer basket with a bit of space between each so steam circulates (work in batches if needed). Place basket over simmering water, cover, and steam for 6–8 minutes until wrapper turns translucent and filling reaches 74°C/165°F. If steaming from refrigerated, add 1–2 minutes. Do not over-steam or gyoza may become overly soft.

Finish & keep warm

Carefully remove the steamer basket and transfer gyoza to a warmed serving tray or chafing dish for buffet service. Brush lightly with a few drops of sesame oil or sprinkle toasted sesame seeds and chopped cilantro or chives for garnish. Keep covered loosely to retain steam and heat.

Dipping sauce

Whisk together 1/4 cup soy sauce, 1/4 cup rice vinegar, 1 teaspoon chili oil, 1/2 teaspoon sesame oil, and 1/2 teaspoon sugar until sugar dissolves. Stir in thinly sliced scallion. Taste and adjust: add more chili oil for heat or a dash more sugar if too tangy. Transfer to a small bowl to place beside the gyoza on the buffet.