Black Walnut Cake I

Ingredients

• 1 cup butter
• 1/2 cup shortening
• 1 1/2 cups packed brown sugar
• 1 1/2 cups white sugar
• 5 eggs
• 3 cups sifted all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 1 cup milk
• 1 teaspoon vanilla extract
• 1 cup chopped black walnuts
• 1 (8 ounce) package cream cheese
• 1/4 cup butter
• 4 cups sifted confectioners' sugar
• 1 teaspoon vanilla extract
• 1/2 cup chopped black walnuts