Preheat oven to 350°. Line a 13×9-inch baking pan with foil, letting excess extend over sides of pan; spray foil with baking spray with flour.
In a large bowl, whisk together brown sugar and melted butter until smooth. Whisk in eggs and vanilla until combined.
In a small bowl, whisk together flour, baking powder, salt, cinnamon, allspice, and ginger. Stir flour mixture into sugar mixture just until combined. Stir in carrots, pecans, raisins, and pineapple. Spread batter into prepared pan.
Bake until a wooden pick inserted in center comes out clean, 20 to 25 minutes. Let cool completely on a wire rack.
In a small bowl, whisk together cream cheese, confectioners’ sugar, and milk until smooth and well combined.
Using excess foil as handles, remove from pan, and cut into bars. Drizzle cream cheese mixture onto bars. Store in an airtight container for up to 3 days.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/carrot-cake-bars/