Ingredients
250 g unsalted butter
210 g all-purpose flour
2 tsp baking soda
0.5 tsp baking powder
1.5 tsp ground cinnamon
0.5 tsp ground allspice
0.5 tsp ground nutmeg
0.5 tsp salt
200 g firmly packed dark brown sugar
4 eggs, at room temperature
1.5 tsp vanilla extract
300 g shredded carrots
60 g chopped walnuts
60 g raisins
85 g unsalted butter
225 g cream cheese, softened
375 g powdered sugar
1 tsp vanilla extract
1 pinch salt
Directions
Step 1
In a light-colored saucepan over medium heat, melt the butter. Cook and swirl constantly until the butter turns nutty brown and browned bits form at the bottom of the pan, about 5 to 10 minutes. Remove from heat and transfer the brown butter to a heat-safe bowl. Allow it to cool to room temperature, about 15 minutes.
Step 2
Preheat the oven to 165°C (325°F). Grease a 30x40 cm pan and line it with parchment paper.
Step 3
In a bowl, whisk together the flour, baking soda, baking powder, cinnamon, allspice, nutmeg, and salt until well combined.
Step 4
In a large bowl, beat the cooled brown butter and brown sugar with an electric mixer on medium speed until well combined. Beat in the eggs one at a time, mixing well after each addition until the mixture is light and fluffy. Mix in the vanilla. Gradually add the flour mixture, mixing until just combined. Fold in the shredded carrots, walnuts, and raisins. Pour the batter into the prepared pan and smooth out the top with a spatula.
Step 5
Bake in the preheated oven until the cake is golden and a toothpick inserted into the center comes out clean, 23 to 27 minutes. Transfer the cake onto a wire rack and let it cool completely, about 30 minutes.
Step 6
While the cake is cooling, repeat the browning process for the butter to make the frosting. Let it cool to room temperature, about 15 minutes.
Step 7
In a large bowl, beat the cream cheese with an electric mixer on medium-high speed until completely smooth. Add the cooled brown butter and mix until thoroughly combined. Mix in the powdered sugar, 1 cup at a time, beating well after each addition. Add the vanilla and salt, and beat the frosting at medium-high speed until completely smooth, 1 to 2 minutes.
Step 8
Spread the frosting over the cooled cake and chill until ready to serve.