Brown Butter Carrot Sheet Cake with Brown Butter-Cream Cheese Frosting

Brown the Butter (5-10 minutes): In a light-colored saucepan over medium heat, melt 1 cup of butter. Swirl the pan constantly as the butter bubbles and transforms into a nutty-smelling, golden-brown liquid with browned bits forming at the bottom. Immediately remove from heat and pour into a heat-safe bowl to cool to room temperature (about 15 minutes).

Prepare for Baking: Preheat the oven to 325°F (165°C). Grease a 12x16-inch sheet pan and line it with parchment paper, leaving an overhang for easy removal.

Whisk Dry Ingredients: In a medium bowl, whisk together the flour, baking soda, baking powder, cinnamon, allspice, nutmeg, and salt until thoroughly combined.

Cream Brown Butter and Sugar: In a large bowl, using an electric mixer on medium speed, beat the cooled brown butter and brown sugar until well combined and creamy.

Incorporate Eggs and Vanilla: Beat in the eggs, one at a time, mixing well after each addition until the mixture is light and fluffy. Stir in the vanilla extract.

Combine Wet and Dry Ingredients: Gradually add half of the dry ingredients to the wet ingredients, mixing until just combined. Repeat with the remaining dry ingredients, mixing until just combined. Be careful not to overmix.

Fold in Add-ins: Gently fold in the shredded carrots, walnuts, and raisins until evenly distributed throughout the batter.

Bake the Cake (23-27 minutes): Pour the batter into the prepared sheet pan and smooth the top with a spatula. Bake in the preheated oven until the cake is golden brown and a toothpick inserted into the center comes out clean. Cool completely on a wire rack (about 30 minutes).

Prepare Brown Butter for Frosting (5-10 minutes): While the cake cools, repeat step 1 with the 6 tablespoons of butter to create browned butter for the frosting. Let cool to room temperature (about 15 minutes).

Whip Cream Cheese: In a large bowl, beat the softened cream cheese with an electric mixer on medium-high speed until completely smooth and free of lumps.

Combine Brown Butter and Cream Cheese: Add the cooled brown butter to the cream cheese and mix until thoroughly combined.

Add Powdered Sugar: Gradually add the powdered sugar, one cup at a time, beating well after each addition until the frosting is smooth and creamy.

Flavor the Frosting: Mix in the vanilla extract and salt. Beat the frosting on medium-high speed for 1-2 minutes until light and fluffy.

Frost and Chill: Spread the frosting evenly over the cooled cake. Chill in the refrigerator until ready to serve. This allows the frosting to set and the flavors to meld.