Arkansas Black Walnut Pound Cake

1 cup butter
1/2 cup shortening
3 cups granulated sugar
5 eggs
1 teaspoon rum (optional)
1 teaspoon vanilla extract
3 cups flour
1 teaspoon baking powder
1 cup milk
1 cup chopped black walnuts

Beat butter, shortening and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition. Add rum and vanilla extract to milk. Add baking powder to flour. Alternately add liquid and dry ingredients to batter (starting and ending with liquid).  Stir in walnuts. Pour batter into a greased and floured Bundt pan. Bake at 325 degrees F for about 70 minutes until cake tests done.

Dust with confectioners' sugar when cool.