Preheat and Prep: Preheat the oven to 350°F (175°C). Grease two 9-inch round cake pans with butter and dust with flour, tapping out the excess.
Dry Ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
Mix Sugar and Eggs: In a large mixing bowl, whisk together eggs and both sugars for 3-4 minutes until the mixture is pale and fluffy.
Add Wet Ingredients: Slowly incorporate the vegetable oil and vanilla extract, whisking continuously.
Combine Wet and Dry: Add the dry ingredients in three additions, mixing just until combined after each addition.
Fold in Add-ins: Gently fold in the grated carrots, pineapple, nuts, and raisins.
Prepare for Baking: Divide the batter evenly between the prepared pans and tap gently to release air bubbles.
Bake to Perfection: Bake for 30-35 minutes, checking with a toothpick at 30 minutes. When the toothpick comes out with moist crumbs attached, the cakes are done.
Cool: Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.
Make the Frosting: Beat softened cream cheese and butter until smooth. Gradually add powdered sugar, vanilla extract, and a pinch of salt. Beat until fluffy.
Assemble the Cake: Spread one-third of the frosting on the first layer, add the second layer, and apply a crumb coat. Chill for 30 minutes before applying the final layer of frosting. Decorate as desired.