Step 1

Place pork skin in a small stockpot or large saucepan and add cold water to cover. Bring to a boil; drain and rinse with cold water. Slice skin lengthwise into 1"-wide strips, trimming any fat, then slice strips crosswise into about ¼"-wide pieces. Return skin to same stockpot and add bones, foot, scallions, ginger, wine, and 8 cups cold water. Bring to a boil, skim surface of any foam, and reduce heat. Simmer, skimming often, until liquid is almost opaque and reduced to 2 cups, 60−75 minutes.

Step 2

Strain liquid into a 13x9" baking dish; discard solids. Season with salt and chill until set, at least 2 hours and up to 3 days. If making ahead, cover soup with plastic wrap once jelled.

Step 3

Mix ground pork, scallions, garlic, soy sauce, salt, wine, sugar, oil, ginger, and pepper with chopsticks in a medium bowl, stirring in one direction until it all comes together and a light film forms on the sides of bowl, about 20 seconds.

Step 4

Cut a fine crosshatch pattern in jelled soup to create very small pieces (about ⅛" squares). Scrape into bowl with filling and mix to combine. Cover and chill until ready to use.

Step 5

Place 3 cups flour in a medium bowl. Slowly drizzle in 1 cup very hot tap water, mixing constantly with chopsticks or a fork, until dough starts to hold together in shaggy pieces. Cover bowl with plastic wrap and let rest 15 minutes (this allows flour to hydrate).

Step 6

Add oil and mix until dough comes together and forms a shaggy ball. Transfer to a lightly floured surface and knead, adding more flour as needed to prevent sticking, until dough is very soft, smooth, supple, and just a little bit tacky, about 10 minutes. Dust dough lightly with flour and wrap in plastic. Let rest 1 hour.

Step 7

Mix scallions, ginger, vinegar, and soy sauce in a small bowl; set aside.

Step 8

Place several large cabbage leaves in steamer, leaving about a 1" border around the sides for steam to travel through. Lightly coat cabbage with nonstick spray (a dumpling that sticks is a dumpling that tears) and set steamer next to work station.

Step 9

Divide dough into 4 equal pieces. Working with 1 piece at a time and keeping other pieces covered with plastic wrap, roll out dough with your palms to make 12"-long ropes.

Step 10

Cut each rope into twelve 1"-pieces with bench scraper. Using a ruler as a guide means all your pieces will be the same size, resulting in uniform dumplings. You’ll look like a pro!

Step 11

Working with 1 piece of dough at a time and keeping other pieces covered in plastic wrap (it’s important to keep the dough covered while you work because it dries out very easily), press your thumb into cut side of dough to flatten.

Step 12

Dust very lightly with flour and use dowel to roll out into thin rounds, about 4" in diameter—work from the center moving outward, applying slightly more pressure as you reach the edges to make them a little thinner. Cover with plastic.

Step 13

Lay a wrapper across the upper part of your palm and bottom half of the fingers of your nondominant hand. Spoon 1 Tbsp. filling into wrapper, making sure to get some pieces of jelled soup.

Step 14

Lightly spread out filling with the back of the spoon, leaving at least a ½" border. Spoon a couple more pieces of jelled soup into center of filling. Slightly cup your palm around dumpling and gently grasp edge of wrapper between your thumb and index finger. Position your other thumb and index finger ½" away in the same fashion.

Step 15

Using fingertips on one hand, gently pull and stretch wrapper outward before bringing it in to meet opposite fingers. Carefully fold stretched area in on itself, creating a pleat. Pinch to seal.

Step 16

Rotating dumpling as you work, repeat process to create a series of 18 pleats, leaving a small hole in the center. You’ll probably get only 10 or 12 pleats the first few times you do this; as your skill increases, so will your folds.

Step 17

Cradle dumpling in your palm, gently rotating it and working filling upward so dumpling is shaped like a fig. This step elongates the dumpling, eliminating air between wrapper and filling.

Step 18

Pinch edges together and gently twist to seal. Place dumpling in prepared steamer and cover with plastic wrap.

Step 19

Repeat with remaining wrappers and filling. Work relatively quickly to keep edges of wrappers from drying out while you work.

Step 20

Remove plastic wrap. Place steamer over a large skillet of rapidly boiling water, making sure water doesn’t touch steamer, and cover. Steam dumplings 8 minutes (10 if frozen). Serve directly from steamer with reserved dipping sauce alongside.

Step 21

Do Ahead: Make and freeze dumplings 1 month ahead. Place on parchment-lined baking sheets that have been coated with nonstick spray. Cover with plastic wrap lightly coated with nonstick spray and freeze solid. Transfer to resealable plastic freezer bags. Steam directly from freezer.