Pound Cake with Nutella Swirls

1 cup butter, softened
  1/2 cup shortening
  1 package (3 ounces) cream cheese, softened
  2-1/2 cups sugar
  5 eggs
  3 cups cake flour *
  1 teaspoon baking powder
  1/2 teaspoon salt
  1 cup buttermilk
  1 teaspoon vanilla extract

* Substitute for cake flour : For every cup of cake flour, take one cup of all purpose flour, remove two table spoons of flour, and add two table spoons of corn starch.

Optional : 
 1 13 oz jar of Nutella
OR
  1 13 oz container of any fruit preserves
OR 
  Any fruit/ chocolate spread you like

• In a large bowl, cream the butter, shortening, cream cheese until light and fluffy. Add eggs, one at a time, beating well after each addition. Beat in extracts. Combine the dry ingredients; add to creamed mixture alternately with buttermilk, beating well after each addition.
• Warm nutella (if using nutella) for 30 seconds in microwave.
• Pour one third mixture in a bundt cake pan, apply a ribbon of nutella/ fruit preserves in the layer, pour another layer of cake mixture, apply the rest of nutella/ fruit preserves and scrape off all the cake mixture into the bundt pan.
• Bake at 325° for 1 hour and 20 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pan to a wire rack to cool completely.
• Optional : serve with fresh strawberries or ice cream.