3 c flour (plus more for dusting)
3/4 c warm water
For the filling:
8 oz yukon gold potatoes (about two medium), unpeeled
2 c finely chopped green cabbage (about 1/4 med. head)
1/2 c finely chopped shiitake mushroom caps (about 2 oz) optional
2 tsp minced fresh ginger
1 tsp minced garlic
1/2 c finely chopped yellow onion (about one small onion)
2 scallions, finely chopped
1/2 tsp garam masala
1/4 c finely chopped cilantro
2 Tbs vegetable stock
2 Tbs butter cut into 1/4 pieces at room temp.
vegetable oil , for steaming
Make the dough: Stir together flour and warm water in bowl until a dough forms. Turn dough onto a lightly floured surface, and knead until dough is smooth and springs back slightly when touched, 10-15 minutes. Cover loosely with plastic wrap, and let rest at room temp for one hour.
Make the filling: place potatoes in a saucepan, and cover with cold water by about two inches. Add a large pinch of salt, and bring to a boil. Reduce heat, and simmer until potatoes are tender, 20-25 minutes. Drain and let cool slightly. Peel potatoes, and cut into 1/2" cubes.
Stir together the remaining ingredients, plus 1 tsp of salt in a large bowl. Gently stir in potatoes. Cover, and refrigerate while you roll out the dough.
Divide dough into four pieces. Work quickly, with one piece at a time, keeping the remaining pieces covered with an inverted bowl. Flatten dough into an oblong slightly thinner than the pasta machines widest setting (number 1 on a kitchen aid pasta roller). Feed through machine. Turn dial to next narrower setting. Pass dough through, gently supporting it with the palm of your hand. Continue to press dough, passing it through ever-finer settings, until very thin but still intact. Transfer to a lightly floured cutting board, Using a 3 1/2" round cutter, cut out rounds. Transfer to a lightly floured baking sheet, and dust with flour. Cover with parchment and a barely damp kitchen towel. Repeat, rolling and cutting one sheet at a time.
Lightly moisten edge of one dough round with a finger dipped in water. Cup round in the palm of your hand, spoon one scant tablespoon filling in center. Place the thumb of the hand holding the dumpling over center of filling. Use the thumb and index finger of your free hand to pinch a portion of dough on one side to form a pleat. Make another pleat next to it. Repeat, rotating dumpling slightly as you work your way around, pressing each new pleat so it falls next to the one beside it. The pleats will begin to close around the thumb holding in the filling. Remove thumb, and hold top of pleats while you twist the bottom of the dumpling in the opposite direction. Press with your finger to make a small indentation in the center of the pleats, pinching up edges. Make sure dumpling is tightly sealed and air has been pressed out. return to sheet: cover, and repeat.
Steam dumplings in batches in an oiled steamer insert or bamboo steamer set over simmering water until shiny, 8-10 minutes. Serve with hot sauce.