1. Place sugar, butter, cocoa powder and milk in a pot and cook until the mixture melts completely and is smooth.
2. Add oatmeal and stir well.
3. Chill the mixture in the refrigerator for one to two hours until it becomes firm.
4. Add chopped chocolate and stir.
5. Make flattened balls from the mixture and place on a baking pan.
6. Freeze the cookies for about an hour to become firm.
7. Decorate with melted white chocolate (optional, but really enhances the cookies).