Cake:

• Preheat oven to 350°F. Grease metal 13- x 9-inch cake pan with 1/2 tsp oil and dust with flour. Set aside.
• In small bowl, stir carrots with buttermilk; set aside. In separate bowl, whisk together flour, cinnamon, baking powder, baking soda, ginger, salt, nutmeg, allspice and cloves. Using electric mixer on high speed, beat together eggs, granulated sugar, brown sugar and vanilla for 3 to 5 minutes or until pale and thickened.
• Reduce speed to medium-low; slowly pour in remaining oil in steady stream. Alternately add flour mixture in 3 additions and carrot mixture in 2 additions, starting and ending with flour mixture, until smooth. Fold in walnuts, and raisins (if using). Scrape into prepared pan and smooth top.
• Bake for 45 to 50 minutes or until tester inserted in center of cake comes out clean. Let cool in pan for 10 minutes; turn out onto rack. Let cool completely.

Frosting:

• In large bowl, stir together mascarpone, icing sugar, vanilla, orange zest and salt until smooth and well combined. Using electric mixer on high speed, beat cream until stiff peaks form when beaters are lifted. Fold gently into mascarpone mixture; spread over cake. Serve immediately or cover tightly and refrigerate for up to 3 days.

Tip: Mascarpone is an Italian cream cheese that is much richer than traditional cream cheese; it’s less tart with a creamier texture. If desired, substitute brick-style cream cheese for the mascarpone and increase icing sugar to 1/2 cup.