My mom has been making rum cakes forever, she has used actual rum and it makes the cake very bitter!! Her recipe is 1/4 cup sugar, 1/4 cup water, and 1 stick of butter. cook down until semi thick, take off of heat and and 1 small bottle of rum flavoring. Pour over cooled cake. If you could find a bourbon flavoring it would work the same way, but everyone loves this "rum cake" and actually think there is real rum in it. She does not ice it, but a cream icing would be good. It is 1 cup Crisco, 2 lbs of powdered sugar, 1 tsp of vanilla and enough water to make the frosting workable. (start with tablespoons) I hope this helps, GOOD LUCK!!!