Mix the sugar and water in a sauce pan over moderate heat, stirring until the sugar is dissolved. Bring to a boil. Peel plantain and add to the boiling sugar syrup. Add the plantain and cook for about 5 minutes. Remove the plantain and drain. Butter a 9-inch square cake pan heavily. Spread the plantain slices evenly over the bottom.
Sift together the flour, salt, baking soda, ginger, cinnamon, cloves, and nutmeg.
Place the butter and molasses in a sauce pan over moderate heat and bring to a boil. Remove from the heat. Combine this heated mixture and the boiling water and stir. Gradually add the sifted dry ingredients, stirring, and then beat vigorously. Pour the batter over the sliced plantain. Bake at 350 degrees F for about 50 minutes, or until the cake tests done. Let the pan stand for 5 minutes on a rack, then loosen with a spatula and turn the cake upside down on a serving plate. Cut into squares. The cake is topped with shipped cream. Serve warm or cooled.