Preheat oven to 350. In a standard mixer, blend your sugar, oil, eggs, and pineapple together.
Then sift your flour, baking powder, baking soda, salt, cinnamon, allspice altogether. Add the flour mixture slowly to pineapple mixture until blended. Then add vanilla, carrots, and walnuts.
Pour batter into a sprayed 13x9 baking dish. Bake one hour or until cake tests done in the center. Remove from oven and let cool one hour.
Frosting-In your mixer blend the confectioners sugar, butter, cream cheese, and half & half plus the vanilla. Mix on medium speed until creamy scraping sides once or twice. Then spread evenly over top of cooled cake. Enjoy!