Add the flour and sourdough discard to a mixing bowl and start with 100 g water.

Mix until a shaggy dough forms.

Knead until everything comes together. If the dough feels too dry, add water 1 tablespoon at a time; if it feels sticky, dust with flour 1 tablespoon at a time.

Knead the dough for 8–10 minutes by hand (or 5–6 minutes in a mixer) until the surface is smooth and elastic.

Cover the dough tightly and let it rest at room temperature for 45 minutes.

In a bowl, combine the ground beef, green onions, ginger, garlic, and soy sauce.

Mix them all gently with a fork or your hands until they are just combined (about 30 seconds). Do not overmix.

Cover and refrigerate the filling until you're ready to use it.

Divide the rested dough in half. Keep the half you aren't working with covered to prevent it from drying out.

Using a rolling pin, roll out the dough into a sheet about 1/16 inch thick and then cut rounds with a 3-inch cutter. Cover the wrappers with a damp towel to keep them moist. Tip: If the dough snaps back while rolling, let it rest another 10–15 minutes. This is normal.

Place about 1 1/2 teaspoons of filling in the center of each wrapper.

Lightly moisten the edges with water.

Fold the wrapper in half to form a half-moon shape.

Starting at one end, make 3–4 small pleats along the edge, pressing firmly as you go to seal the dumpling completely. Avoid overfilling.

Heat 1–2 tablespoons of oil in a skillet over medium heat.

Add the dumplings in a single layer and cook them until the bottoms are golden brown (about 2–3 minutes).

Add 1/4 cup water, cover, reduce the heat to low and steam them for 5–7 minutes.

Remove the lid and cook until the water evaporates and the bottoms crisp up again.

Serve immediately.