Preheat oven to 350. Prepare a loaf pan with cooking spray and flour; set aside. To prepare batter, combine granulated sugar, flour, baking soda, cinnamon, salt, and carrots in a mixing bowl. In another mixing bowl, combine crushed pineapple, 2 teaspoons vanilla extract, oil, and egg whites. Mix dry ingredients with wet ingredients just until moistened. Mixture will be thick. Pour mixture into prepared pan. Bake, for 1 hour. Meanwhile, to prepare topping, combine cream cheese, powdered sugar, and remaining vanilla extract in a small mixing bowl. Blend until smooth. Spread over cooled cake.
BETSY'S NOTE: Bake in a shallow baking pan (11x7" maybe?) rather than a loaf pan.