Ingredients

1 1/4 cups unsalted butter, room temperature, plus more for pan 

2 cups light-brown sugar 

5 large eggs, separated 

Zest and juice of 1 orange 

1 slightly heaped teaspoon baking powder 

1 heaped teaspoon ground cinnamon 

Pinch of ground cloves 

Pinch of ground nutmeg 

1/2 teaspoon ground ginger 

1 cup ground almonds 

4 ounces shelled walnuts, chopped, plus more for garnish 

1 1/2 cups self-rising flour, sifted 

10 ounces carrots, peeled and coarsely grated 

Sea salt 

4 ounces mascarpone cheese 

8 ounces cream cheese, room temperature 

1 scant cup confectioners' sugar, sifted 

Zest and juice of two limes 

Preparation

Preheat oven to 350 degrees. Butter a 9-by-2-inch square baking pan and line with parchment paper. Set aside.

In the bowl of a food processor, pulse together butter and brown sugar until pale and fluffy. Add egg yolks, one at a time, pulsing after each addition. Add orange zest and juice; pulse to combine. Add baking powder; pulse to combine. Add cinnamon, cloves, nutmeg, and ginger; pulse until mixture is well combined.

In a large bowl whisk egg whites with a pinch of salt until stiff. Gently fold in almonds, walnuts, flour, and carrots; fold cake mixture into egg white mixture. Pour batter into prepared pan and bake until golden and a toothpick inserted into the center comes out clean, about 1 hour. Let cake cool in the pan 10 minutes before turning out onto a wire rack to cool completely.

In a medium bowl, mix together mascarpone, cream cheese, confectioners’ sugar, and lime zest and juice. Spread mixture over top of cooled cake and sprinkle with chopped walnuts.