Adapted from the book Williams Sonoma baking essentials but altered a bit. Subsittuting agave for the sugar and applesauce for a large part of the oil does not compromise taste at all. This healthier for you version tastes great!
Preheat an oven to 350°F Butter and flour a 9-by-13-by-2-inch baking pan.
To make the cake, peel and grate the carrots. You should have about 3 cups. Set aside.
Over a sheet of parchment paper or a plate, sift together the flour, baking powder, baking soda, salt, cinnamon and mace. Set aside.
In a large bowl, combine the agave, eggs, oil, applesauce and orange zest and whisk thoroughly to combine. Stir in the carrots. Using a rubber spatula, fold in the flour mixture until almost completely incorporated. Add the raisins and nuts and fold to mix thoroughly. Pour the batter into the prepared pan.
Bake the cake until a toothpick inserted into the center comes out clean, 35 to 40 minutes. Watch the time closely at the end so the cake does not overbake. It might have to bake a little longer if you use a different type of pan so just keep checking it and inserting a toothpick until it comes out clean. Transfer the pan to a wire rack and let cool for 15 minutes. Place a cake rack on top of the pan, invert them together and lift off the pan. Let the cake cool completely. Cover the cake with a slightly damp clean kitchen towel so the outside does not dry out as it cools.
Transfer the cooled cake to a serving platter. Using an icing spatula, frost the cake with a thick layer of frosting. Serve immediately, or store in an airtight container at room temperature for up to 3 days. Makes one 9-by-13-inch cake.