Place vegetable oil in a deep saute pan that comes no more than 1/3 of the way up the sides of the pan. Heat until a deep fat fry thermometer registers 360 degrees. Meanwhile, in a medium saucepan, place the plums, sugar, ginger and cardamom and cook for 10 minutes. The sugar and the plums will form their own syrup. In a bowl combine the cornstarch and water until they form a paste. While stirring, slowly pour the cornstarch paste into the plum mixture. The mixture should thicken right up. Cook for 1 minute, stirring constantly. Remove from the heat and cool slightly. Place 1 1/2 teaspoons of the filling in the center of the round dumpling wrapper. Using your fingertips, moisten the edges of the wrapper with a little water, and fold the sides of the wrapper towards the center and press the edges closed. Continue until all the wrappers are filled. Carefully drop the dumplings into your saute pan 4 to 5 at a time. Fry until golden, about 3 to 4 minutes. With a slotted spoon remove from the oil and drain on paper towels, drizzle with ginger syrup, or honey. Cover with a generous shake of powdered sugar