Make the sauce: In a small bowl dissolve the cornstarch in 3/4 cup cold water and stir in the oyster sauce, the soy sauce, the oil, the sugar and the white pepper.
In a wok or kettle bring 8 cups water to a boil, add the clams and boil them, stirring occasionally, for 4 to 7 minutes, or until they begin to open, transferring them as soon as they open with a slotted spoon to a large bowl. Discard any unopened clams and the cooking liquid.
In the wok, dried and heated, heat the oil over high heat until it just begins to smoke, add the gingerroot, the garlic and the black beans and stir-fry the mixture until the garlic is golden. Add the clams and stir-fry the mixture for 1 to 2 minutes, or until the clams are coated well. Make a well in the center of the clam mixture, stir the sauce, and pour it into the well. Bring the mixture to a boil, stirring, and stir it until the clams are coated well with the sauce. Transfer the clam mixture to a serving dish and sprinkle it with the scallion.
*available at Asian markets.
Recipe courtesy of Gourmet Magazine