1. Combine the sugar, cream and melted butter or margarine and beat until light and creamy. Stir in the coconut.
2. Spread the mixture over spice cake, plain cake or gingerbread baked in an 8- or 9-inch square pan, immediately upon removing it from the oven.
3. Return the cake to the oven, setting it under Moderately Low broiler heat, until the icing is bubbly. Remove at once from the oven. Cut when the icing has cooled.