1. Grease a 7 inch round cake pan and line the base.
2. Place the egg whites, superfine sugar and coconut in a saucepan. Heat gently for a few minutes, stirring carefully with a wooden spoon until mixture is hot and the sugar is dissolved (about 140 degrees on a candy thermometer). Leave until cold.
3. Place the molasses, light brown sugar and butter in a saucepan; heat gently until melted.
4. Sift the dry ingredients together, then add to the butter mixture with the eggs and rum. Beat well.
5. Pour half of the mixture into the pan. Spoon the coconut mixture into the center, then pour over the remaining ginger mixture.
6. Bake in a 325 degree oven for 45-50 minutes until risen and firm to the touch. Cool on cake rack. Freezes well.
Serves 10.
