1) Place the filling ingredients in the bowl of a food processor, reserving the soy, pepper, and salt. Pulse until you have a coarse paste. Most of the filling will be well ground, but you should still have some visible chunks of pork left.
2) Add the soy, pepper, and salt to the filling. To check the flavor, microwave a small portion and taste. Set the filling aside at room temperature for 30 minutes to blend the flavors; or refrigerate overnight.
3) To make the dumpling dough: Place the flour in a heat-proof bowl. Pour the boiling water over the flour and stir until the flour begins to bind into a ball.
4) When the dough is just cool enough to handle, knead it until it's smooth and almost dry. This dough should be moist under your hands, but not sticky in any way. Add small amounts of flour as you knead to get the right consistency.
5) Place the still-warm dough in a large plastic bag and seal shut. Set aside at room temperature for 30 minutes. The dough will continue to hydrate and the starches will pre-cook a little in the heat, giving you a very pliable dough.
6) When you're ready to assemble the dumplings, remove the filling from the fridge and let it come to room temperature if necessary. Divide the dough into small, 1"-sized pieces. Use your fingers to roughly shape each piece into a small disc.
7) Using a small dowel or rolling pin and working from the center outward, roll the piece of dough into flat circles about 3" across. Try to leave the center a bit thicker than the edges, as this will be the bottom of your wrapper, and you want it to be sturdy. Repeat with about a dozen of the discs, keeping the others covered while you work to prevent drying.
8) Place 2 teaspoons of filling in each wrapper. You don't want them to be overstuffed, as they'll break open during cooking, so play with the amount of filling until you get it just right for you.
9) Fold the sides of the dough over the filling in a half-moon shape, like you were making a turnover. Pinch the edges of the dough together to seal. You can leave the edges plain, or you can fold over and crimp with your fingers. Check out our blog link at the top of the recipe to see the entire process in pictures.
10) At this point you can place the filled dumplings on a baking sheet and freeze until solid. Store in a zip-top or airtight container for up to 4 weeks. Or boil or steam the dumplings right away.
11) To steam the dumplings: Place a round cooling rack in the bottom of a large sauté pan with a cover. Add about 1/2" of hot water and set over medium heat. Place the dumplings on the rack and cover the pan. Steam for about 8 to 10 minutes; "sacrifice" one dumpling near the end of the cooking time, cutting it open to ensure the filling is cooked all the way though.
12) Serve the dumplings hot, with soy sauce or dumpling sauce for dipping. Store leftovers, if any, in the fridge for 2 days. Reheat briefly in the microwave.
Yield: 2 to 3 dozen dumplings, depending on size.