Elegant Orange Cake - California Raisins

Ingredients

• 3 1 / 2 Cups sifted cake flour
• 2 Teaspoons baking soda
• 1 / 2 Teaspoon salt
• 1 / 2 Cup butter or margarine
• 1 / 2 Cup shortening
• 1 1 / 2 Cups sugar
• 4 eggs
• 1 1 / 2 Cups buttermilk
• 2 Teaspoons orange extract
• 1 Cup California raisins, finely chopped
• 1 Cup walnuts, finely chopped
• 1 / 3 Cup butter or margarine, softened
• 4 Cups (1 pound) powdered sugar
• 1 / 4 Cup orange juice
• Grated orange peel (optional)