Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans (or line with parchment paper for easier release).

In a large bowl, whisk together the flour, sugar, baking powder, baking soda, cinnamon, nutmeg, and salt until well blended.

In another bowl, combine the vegetable oil, eggs, grated carrots, crushed pineapple, and vanilla extract. Mix until well combined.

Gradually add the wet mixture to the dry mixture and blend until just combined. Fold in the chopped nuts if using.

Divide the batter evenly between your prepared pans and smooth the tops.

Bake in the preheated oven for 25-30 minutes. Check for doneness with a toothpick; it should come out clean.

Let the cakes cool in the pans for about 10 minutes, then transfer them to wire racks to cool completely.

In a mixing bowl, whip together cream cheese, butter, and powdered sugar until smooth and fluffy.

Once the cakes are completely cool, frost between layers, and cover the top and sides as desired.

Slice into generously-sized pieces and enjoy!