Have on hand a 9-inch spring-form pan and a roasting pan. Cut a sheet of foil and cover the bottom and sides of the spring-form pan.
In a bowl, combine 6 Tbsp of the sugar and the hot water. Stir well.
In a saucepan, combine the olive oil and chocolate. Cook over low heat, stirring occasionally until the chocolate melts. Turn off the heat. Stir the sugar mixture, then stir it into the chocolate mixture until smooth. Set aside to cool slightly.
Set the oven at 300 degrees.
In an electric mixer, beat the eggs. Gradually beat in the remaining 7 Tbsp sugar and continue beating for 10 minutes or until lemon-colored.
Add the chocolate mixture and beat until smooth. Pour the batter into the spring-form pan and set it in the roasting pan. Place in the middle of the oven. Pour very hot water into the roasting pan to come ¼ inch up the sides of the spring-form.
Bake the cake for 40-45 minutes or until it is just set in the center. Lift out the spring-form. Cool to room temperature. Refrigerate until cold.
Un-latch the spring-form. Slice with a warm knife, cleaning the blade after each slice. Makes 16 slices. Garnish with berries and mint.