A three layer carrot cake, with raisins, nuts and a white chocolate frosting is bound to make everyone smack their lips.
Preheat oven to 350F.
Line the bottoms of 3 round cake pans with parchment circles and grease with butter. Set aside.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cocoa, and cinnamon. Sift the flour mixture onto a large piece of parchment.
In mixing bowl using an electric mixer, beat the granulated sugar, brown sugar, oil, eggs, and vanilla on medium speed for 1 minute, or until well blended.
Add the flour mixture and beat on low speed for about 20 seconds, just until incorporated. Add the carrots, half the raisins, and all of the nuts, if using, and beat for another 12 seconds.
Divide the batter evenly into the prepared pans and smooth the surface with a small offset spatula.
Each will be just under half full. If using them, scatter the remaining raisins evenly on top of the batter in each pan. Use the back of a fork to push them gently into the batter.
Bake for 25 to 35 minutes, or until a cake tester inserted in the centers comes out clean and the cakes spring back when pressed lightly in the centers.
The cakes should just start to shrink from the sides of the pans.
Let the cakes cool in the pans on a wire rack for 10 minutes. Run a small metal spatula between the sides of the pans and the cakes, pressing firmly against the pans, and invert the cakes onto wire racks.
To prevent splitting, re-invert the cakes so that the tops are up. Cool completely.
Heat the chocolate until almost completely melted.
Use the top of a double boiler set over hot, not simmering, water, stirring often – do not let the bottom of the container touch the water. OR, Use a small microwavable bowl, stirring with a silicone spatula every 15 seconds.
Remove the white chocolate from the heat and using a silicone spatula, stir until fully melted.
Allow to cool until it is no longer warm to the touch but is still fluid.
In the bowl of a food processor, process the cream cheese, butter, and crème fraiche for a few seconds until smooth and creamy. Scrape down the sides.
Add the cooled melted white chocolate and pulse it in a few times until it is smoothly incorporated.
If the frosting seems too soft to spread on the cake, you can put it in the refrigerator for a few minutes to firm up.
Spread a little of the frosting on a 9-inch cardboard round or serving plate.
Set one cake layer on the frosting smear. This will help keep the cake from sliding around.
Spread frosting over the top of the cake layer, stopping just before the edges.
Repeat with layers.
Frost the top and sides with the remaining frosting. Remove the paper slips from beneath the cake and discard.