Place the all-purpose flour and salt in a large bowl and mix. Pour the boiling water into the flour gradually while stirring with a wooden spoon or chopsticks until the mixture clumps together into coarse lumps.

Knead

When cool enough to handle, add the cold water and knead in the bowl until a shaggy dough forms. Transfer to a lightly floured surface and knead for 6–8 minutes until smooth and elastic. If dough is too sticky, dust lightly with flour; if too dry, wet fingers and continue kneading.

Rest

Cover the dough with a damp cloth or plastic wrap and let rest for 30 minutes at room temperature. Resting relaxes the gluten and makes rolling easier.

Divide and roll

After resting, divide the dough into two equal portions. Keep one portion covered while working with the other. Roll one portion into a log about 1.5–2 inches (4–5 cm) in diameter. Cut into 12 equal pieces (for ~24 small wrappers) and roll each piece into a small ball. Flatten each ball with your palm, dip both sides lightly in cornstarch, and roll into thin rounds about 3–3.5 inches (7.5–9 cm) across using a rolling pin. Keep finished wrappers covered with a damp cloth to prevent drying.

Filling (Pork & Shrimp)

Prepare shrimp

Pat shrimp dry and chop coarsely — leaving some small pieces for texture. Keep chilled.

Mix filling

In a medium bowl combine ground pork, chopped shrimp, sliced green onions (reserve a little for garnish), grated ginger, minced garlic, soy sauce, oyster sauce, sesame oil, Shaoxing wine, sugar, white pepper, salt, cornstarch, and egg white. Stir firmly in one direction (or use a fork) until the mixture becomes slightly sticky and homogeneous, about 1–2 minutes. This helps bind and tenderize the filling. Taste a small piece by frying a teaspoon quickly and adjust salt or soy sauce as needed.

Assembly & Cooking

Fill and shape (potsticker/guo tie style)

Place a wrapper on your palm. Put about 1 teaspoon (heaping) of filling in the center. Lightly brush the edge of the wrapper with water (use fingertip). Fold the wrapper in half and pleat one side to seal into a potsticker shape, pressing to close completely. Repeat until all wrappers are filled. Keep finished dumplings covered with a damp cloth.

Pan-fry then steam (classic crispy-bottom)

Heat a nonstick or well-seasoned skillet over medium-high heat. Add 2 tablespoons vegetable oil and swirl to coat. Place dumplings flat-side down in the pan in a single layer, leaving a little space between them. Fry 2–3 minutes until bottoms are golden brown. Carefully pour 1/4 cup water into the pan (it may steam and sputter), immediately cover with a tight-fitting lid and reduce heat to medium-low. Steam for 5–6 minutes until filling is cooked through (pork should reach 70°C/160°F and shrimp turn opaque). Remove lid and uncover; continue cooking 1 minute to re-crisp the bottoms. Transfer dumplings to a plate.

Brush and garnish

Lightly brush cooked dumplings with a little oil if desired, sprinkle with sesame seeds and reserved sliced green onion.

Dipping Sauce (optional)

Whisk together soy sauce, black or rice vinegar, sesame oil, chili oil (or chili flakes), and sugar in a small bowl until sugar dissolves. Adjust balance to taste: more vinegar for tang, more soy for saltiness, or a pinch more sugar to round flavors.