Preheat the oven to 350°F (175°C). Gather your mixing bowls, measuring cups, and a whisk.

Grease a 9x13-inch baking pan or two 9-inch round cake pans with vegetable oil. Line the bottom with parchment paper.

In a large bowl, combine the dry ingredients: flour, baking powder, baking soda, salt, cinnamon, and nutmeg. Whisk until evenly blended.

In another bowl, whisk together the vegetable oil, granulated sugar, and eggs until smooth.

Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.

Fold in the grated carrots and any optional chopped nuts or dried fruits until evenly distributed.

Pour the batter into the prepared pans and bake for 40-45 minutes, or until a toothpick comes out clean.

Remove from the oven and let cool in the pans for about 10 minutes. Then, transfer to a wire rack to cool completely.

To prepare the frosting, beat the cream cheese until smooth, then gradually mix in the powdered sugar.

Once the cake layers are cool, frost between the layers and the outside of the cake.