Preheat oven to 350 degrees F (175 degrees C). Grease one 9 or 10 inch tube pan.
Boil water add rum and raisins. Melt butter and beat egg. Add to the raisin mixture.
Sift flour, baking soda, cocoa, and sugar together. Stir into raisin mixture. Add chopped pecans and stir until just combined. If batter is too thick add a little more water. Pour batter into prepared pan.
Bake at 350 degrees F (175 degrees C) for 40 to 50 minutes. Let cake cool in the pan for 10 minutes then turn out onto a serving dish. Serve cake hot with custard or top cooled cake with whipped cream.
