• Preheat the oven to 350 degrees Fahrenheit. Spray a 10 x 15 x 1 baking sheet (jelly roll pan) with nonstick cooking spray and set aside.
• Whisk together 2 ½ cups flour, 2 teaspoons ground cinnamon, ½ teaspoon ground nutmeg, ½ teaspoon ground ginger, ¼ teaspoon ground cloves, ½ teaspoon baking soda, 1 ½ teaspoons baking powder, and 1 teaspoon salt in a medium bowl and set aside.
• Add 1 cup vegetable oil, 1 cup packed light brown sugar, and 1 cup granulated sugar to a large bowl and mix until combined. Add 3 large eggs and 2 teaspoons vanilla extract and mix until combined.
• Add the flour mixture to the sugar mixture and mix until just combined.
• Fold in 2 cups shredded carrots until evenly dispersed in the batter. Pour the batter into the prepared pan and spread it evenly.
• Bake for 28-34 minutes, until a toothpick comes out clean from the center. Remove the bars from the oven and let them cool completely.

Frosting

• Add ½ cup room temperature unsalted butter and 6 ounces softened cream cheese to a large bowl and beat on medium-high speed with a hand mixer or stand mixer fitted with the paddle attachment until smooth. Scrape down the sides and bottom of the bowl to ensure it is all incorporated evenly.
• Add 3 cups powdered sugar, 2 teaspoons vanilla extract, and 1 large pinch salt to the bowl and beat until smooth.
• Spread the frosting evenly over the top of the cooled carrot cake. Cover and store in the refrigerator until you are ready to slice it into bars and serve.