Making the Carrot Cake Batter:

1. Preheat & Prepare Pans: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. For extra insurance against sticking, line the bottoms with parchment paper rounds, then grease and flour the parchment and sides.
2. Whisk Dry Ingredients: In a large bowl, whisk together the all-purpose flour, baking soda, salt, cinnamon, ginger, nutmeg, and cloves (if using). Whisking well helps distribute the leavening agents and spices evenly. Set aside.
3. Combine Wet Ingredients: In a separate large bowl (or the bowl of your stand mixer fitted with the whisk attachment), whisk together the granulated sugar, packed light brown sugar, and vegetable oil until well combined.
4. Add Eggs & Vanilla: Add the eggs one at a time, beating well after each addition until the mixture is smooth and slightly thickened. Beat in the pure vanilla extract.
5. Combine Wet and Dry: Gradually add the dry ingredient mixture to the wet ingredient mixture, mixing on low speed (or gently by hand with a spatula) only until just combined. Be careful not to overmix at this stage, as it can lead to a tough cake. Some streaks of flour remaining are okay.
6. Fold in the Goodies: Gently fold in the finely grated carrots, the well-drained crushed pineapple (if using), toasted nuts (if using), and raisins (if using) using a rubber spatula. Fold until everything is evenly incorporated, ensuring you scrape the bottom of the bowl. Again, avoid overmixing.

Baking the Cake Layers:

1. Divide Batter: Divide the batter evenly between the two prepared cake pans. Smooth the tops with your spatula.
2. Bake: Place the pans in the preheated oven on the center rack. Bake for 30-40 minutes, or until a wooden skewer or toothpick inserted into the center of the cakes comes out clean or with a few moist crumbs attached. Baking times can vary depending on your oven, so start checking around the 30-minute mark. The tops should spring back lightly when gently pressed.
3. Cooling Process (Crucial!): Once baked, remove the cakes from the oven and let them cool in the pans on a wire rack for 15-20 minutes. This allows the cakes to firm up slightly so they don’t break when inverted.
4. Invert and Cool Completely: Carefully run a thin knife or offset spatula around the edges of the cakes to loosen them. Invert the cakes onto the wire rack, peel off the parchment paper (if used), and let them cool completely to room temperature. This can take 1-2 hours. Do not attempt to fill or frost warm cakes, as the mousse will melt. For best results and easier handling, you can wrap the cooled cake layers tightly in plastic wrap and chill them in the refrigerator for at least 30 minutes (or even overnight) before assembling.

Preparing the Cream Cheese Mousse Filling:

This should be done when the cake layers are completely cool.

1. (Optional Gelatin Step for Stability): If using gelatin, sprinkle the powdered gelatin over the 2 tablespoons of cold water in a small microwave-safe bowl. Let it sit for 5-10 minutes until it blooms (it will look like applesauce). Microwave on high for 5-10 seconds, just until the gelatin liquefies. Stir and set aside to cool slightly (it should be liquid but not hot).
2. Beat Cream Cheese: In a large bowl, using an electric hand mixer or a stand mixer fitted with the paddle attachment, beat the softened block cream cheese on medium speed until completely smooth and creamy, with no lumps. This might take 2-3 minutes. Scrape down the sides and bottom of the bowl frequently.
3. Add Sugar and Vanilla: Gradually add the sifted powdered sugar, mixing on low speed until incorporated, then increase the speed to medium and beat until smooth and light. Beat in the vanilla extract. Scrape the bowl again.
4. Whip Heavy Cream: In a separate, clean, cold bowl, whip the cold heavy cream using clean beaters (or the whisk attachment of your stand mixer) on medium-high speed until stiff peaks form. Be careful not to overwhip it into butter. Stiff peaks mean that when you lift the beaters, the peak holds its shape and doesn’t flop over.
5. Combine (with Gelatin if used): If using gelatin, ensure it’s slightly cooled but still liquid. With the mixer on low speed, slowly drizzle the liquefied gelatin into the cream cheese mixture and mix until just combined. Immediately proceed to the next step.
6. Fold in Whipped Cream: Gently fold about one-third of the whipped cream into the cream cheese mixture using a large rubber spatula to lighten it. Then, gently fold in the remaining whipped cream in two more additions. Fold just until no streaks of white remain. Be gentle to maintain the airy texture of the mousse. Do not overmix, or the mousse will deflate.
7. Chill Briefly (Optional but helpful): If the mousse seems very soft, you can cover the bowl and chill it in the refrigerator for 15-30 minutes to firm up slightly before assembling the cake. This makes it easier to spread.

Assembling the Carrot Cake:

1. Level the Cakes (Optional): If your cake layers have domed tops, you can use a long serrated knife to carefully level them for a more stable and even cake. (Save the scraps for snacking!)
2. Place First Layer: Place one cooled (and possibly chilled) cake layer, top-side down (flat side up), onto your serving plate or cake stand. If desired, place strips of parchment paper under the edges of the cake to keep the plate clean during assembly; you can slide them out later.
3. Apply Mousse Filling: Scoop about half to two-thirds of the cream cheese mousse onto the center of the first cake layer. Using an offset spatula, gently spread the mousse evenly over the cake layer, right to the edges. The mousse layer should be generous – this is the star filling!
4. Add Second Layer: Carefully place the second cake layer on top of the mousse, top-side up (or top-side down if that side is flatter). Press down gently to adhere it.
5. Frost the Cake (Optional): You have a few options here:

   • Mousse Frosting: Use the remaining cream cheese mousse to frost the top and sides of the cake. It will be a softer, lighter frosting than traditional cream cheese frosting. A “naked” or “semi-naked” look (where some cake shows through the sides) works well with the mousse.
   • Traditional Frosting: If you prefer a thicker, more traditional frosting for the outside, you can make a separate batch of standard cream cheese frosting (using cream cheese, butter, powdered sugar, vanilla) to cover the top and sides after the mousse filling has been applied between the layers.
   • Simple Top: Just frost the top of the cake with the remaining mousse and leave the sides bare.

6. Decorate: Garnish the cake as desired. Toasted chopped pecans or walnuts pressed around the base or sprinkled on top are classic. You can also add small piped carrots (using tinted frosting), a dusting of cinnamon, or fresh carrot curls (made with a vegetable peeler).
7. Chill to Set: Crucial Step! Cover the cake loosely (a cake dome is ideal, or use toothpicks to tent plastic wrap so it doesn’t touch the mousse) and refrigerate for at least 2-4 hours, or preferably 6-8 hours or overnight. This allows the mousse filling to fully set and stabilise, and lets the flavours meld beautifully. The cake will slice much more cleanly after chilling.