In saucepan, bring broth and ginger to boil. Reduce heat, cover and simmer 5 minutes. Remove and discard ginger. Dissolve cornstarch in 1 1/2 cups water; stir cornstarch mixture and corn into broth. Over high heat, stir constantly until mixture boils and thickens. Gradually pour egg into boiling soup, stirring gently in one direction. Remove from heat; stir in green onions and soy sauce.