Preheat oven to 325. Spray bottom of 10-inch tube pan with cooking spray.
In a large bowl, cream the butter; gradually beat in the sugar until light and fluffy. Add the eggs, one at a time, beating well after each addition. Add the remaining cake ingredients. Blend at low speed until moistened. Beat 2 minutes at medium speed, scraping the bowl occasionally. Spread the batter evenly into the prepared pan.
Bake for 1 hour, or until the top springs back when lightly touched. While the cake is still hot, prick the top of the cake and pour the butter sauce on top.
To prepare the Butter Sauce: combine the 1 cup sugar, hot water, and ½ cup butter. Heat in a saucepan or in the microwave until the butter is melted---do not boil. Remove from heat, add rum flavoring, and pour over warm cake.