Beat together 1 cup flour, 1 cup ice water, 1 slightly beaten egg, 2 tablespoons salad oil, 1/2 teaspoon sugar, 1/2 teaspoon salt until all ingredients are moist. (A few lumps should remain.) Keep batter cool in refrigerator. Serve with 1 1/2 tablespoons soy sauce and 1/4 cup prepared mustard.