Preheat oven to 350°F (175°C) and grease two 9-inch round cake pans.
In a bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In another bowl, beat vegetable oil, sugar, and brown sugar until combined.
Add eggs one at a time, mixing well, then stir in vanilla.
Gradually mix in dry ingredients, then fold in carrots, pineapple, and pecans.
Divide batter between cake pans and bake for 30-35 minutes.
Let cakes cool completely before frosting.
For frosting, beat cream cheese and butter until smooth, then mix in powdered sugar and vanilla.
Frost the cake and garnish with extra pecans if desired.