1. For the dough, stir the flour, baking powder and sugar in a bowl. Stir in the oil and water to make a soft dough; shape into a ball. Knead on a lightly floured surface until smooth and pliable, 3 to 4 minutes. Return to the bowl, cover with a towel, and let rest 10 to 15 minutes.
2. For the filling, heat the sesame oil in a wok or skillet, add the mushrooms and garlic, stir-fry for 2 to 3 minutes. Add the remaining 5 ingredients, mix well and cook until thick and sticky. Remove to a bowl to cool.