Heat wok with some oil and add in ground pork and shrimp. Stir until almost cook and add in chopped mushroom. Stir for couple minutes and salt, sugar, oyster sauce, five spicy and pepper and then add in water.
Slowly add in cornstarch mixture to thicken sauce. Remove from heat and add in chopped onion and scallion. Stir and leave to cool.
Place wheat starch in a large bowl and add in hot boiling water. Stir with chopsticks until dough cooked. Stir in sugar and mix well. Mix in glutinous rice flour. Stir and add in water to form dough. If dough too wet then add in just a little glutinous rice flour. Knead into dough. Divide into 20 pieces. Fatten dough in rough shape and add in fillings. Form into crescent shape.
Heat oil on medium heat and deep fry the dumplings until golden.