Prepare the Oven and Pans
Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans and line the bottoms with parchment paper for easy removal.

Mix the Dry Ingredients
In a medium bowl, whisk together the flour, baking soda, salt, and ground cinnamon. Set aside.

Combine the Wet Ingredients
In a large mixing bowl, whisk the vegetable oil, granulated sugar, brown sugar, and vanilla extract until well combined. Add the eggs one at a time, whisking after each addition until the mixture is smooth and glossy.

Add the Carrots and Dry Mix
Stir the grated carrots into the wet ingredients. Then, fold in the dry ingredients just until no streaks of flour remain. Do not overmix.

Add the Texture
Gently fold in the chopped pecans and raisins until evenly distributed.

Bake the Cake
Divide the batter evenly between the prepared pans and smooth the tops. Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean. Let the cakes cool in the pans for 10 minutes, then turn out onto a wire rack to cool completely.

Make the Creamy Frosting
Beat the cream cheese until smooth. If using, add the cornstarch and mix until incorporated. Slowly beat in the powdered sugar until fully blended. Gradually add the cold heavy cream and whip on medium-high speed until light and fluffy.

Assemble and Decorate
Once the cakes are fully cooled, spread a layer of frosting between them, then frost the top and sides. Sprinkle the top with chopped pecans. Chill for 30 minutes before slicing for clean layers.