Make the sauce: In a skillet cook the onion in the oil over moderately low heat, stirring, until it is softened, add the gingerroot, and cook the mixture, stirring, for 1 minute. Add the tomatoes with the juice and simmer the sauce, stirring occasionally, for 5 to 8 minutes, or until it is thickened slightly. Season the sauce with salt and pepper and keep it warm. Make the quenelles: Discard the tough bit of muscle clinging to the side of each scallop if necessary and in a food processor puree the scallops with the salt. With the motor running add the cream in a stream and blend the mixture until it is just smooth. In a large deep skillet bring 1 1/2 inches of salted water to a simmer. Scoop out and form oval mounds of the mousse with 2 soup spoons dipped in cold water, dropping each mound as it is formed into the simmering water, and poach the quenelles at a bare simmer, turning them occasionally, for 6 minutes, or until they are springy to the touch. Transfer the quenelles with a slotted spoon to paper towels, let them drain briefly, and divide them between 2 heated plates. Spoon the sauce over and around the quenelles and garnish the quenelles with the parsley. Serves 2. Gourmet October 1991