Wash prawns thoroughly and leave on shells and heads. In a bowl, mix the soy sauce, garlic and brandy. Arrange the prawns on a dish, and cover with the soy sauce mixture.
Fill a pot or wok about half full with water. Place a steamer basket over the water, and bring water to a boil. Place the dish with the prawns onto the steamer basket. Cover wok, and steam prawns for 10 minutes, until opaque. Serve hot.