Heat oven to 350 degrees F. Grease a 9- or 10-inch 2-quart tube pan.
Cake: Cream butter; gradually add sugar and beat until light. Add fruit rinds; add
eggs one at a time, beating thoroughly after each. Add sifted dry ingredients alternately
with buttermilk, beating after each addition until smooth. Fold in nuts. Pour into
prepared tube pan.
Bake for 1 hour.
Pouring Liquid: Strain fruit juices into saucepan. Add sugar and rum; bring to
boil. Pour slowly over hot cake in pan. If all liquid is not absorbed, pour remainder
Grand Marnier Icing: Bring butter to room temperature. Mix all ingredients, adding
enough Grand Marnier to make a good spreading consistency. Spread on cooled cake.