Carrot Sheet Cake with Cream Cheese Frosting

Juicy and lightly spiced, this carrot cake received the highest rating from Our Test Kitchen. For the pie, we will need a metal baking dish; if you are using a glass baking dish that conducts heat better than a metal one, reduce the baking temperature to 325 ° and start checking the readiness after 25 minutes. For the best frosting consistency, use softened butter and cold cream cheese, and add powdered sugar in portions.
Preheat the oven to 350 degrees.To make the pie, brush a 13-inch x 9-inch baking dish with cooking spray; line the bottom of the pan with waxed paper. Brush waxed paper with cooking spray; set aside.Put 9 tablespoons butter, brown sugar and granulated sugar in a large bowl; beat with a mixer on medium speed for 5 minutes or until smooth. Add the eggs and egg whites one at a time, beating well after each addition until pale and fluffy. Whisk with 2 teaspoons vanilla extract.Lightly pour the flour into dry measuring cups; smooth with a knife. Combine the flour, baking soda, cinnamon, and 1/4 teaspoon salt, stirring with a whisk. Add the flour mixture and buttermilk alternately to the sugar mixture, starting and ending with the flour mixture; stir after each addition. Add the carrots. Spoon the batter onto the prepared pan. Tap the mold sharply once on the countertop to remove any air bubbles. Bake at 350 ° C for 30 minutes or until a wooden stick inserted in the center comes out clean. Cool in the pan for 10 minutes on a wire rack; remove from the pan. Carefully remove the wax paper; cool completely on a wire rack.To make the frosting, put the cream cheese, 1/4 cup butter, 2 teaspoons vanilla and 1/8 teaspoon salt in a large bowl; beat with a mixer on medium speed until smooth. Gradually add 2 cups powdered sugar, whisking on low speed until smooth (do not interrupt). Add the remaining 3/4 cup powdered sugar. Cover and chill for 30 minutes. Spread the icing on top of the cake. Garnish with topping. Keep the cake loosely covered in the refrigerator.