Preheat your oven to 350°F (175°C). Prepare your baking pans by greasing them and lining the bottoms with parchment paper.

In a large mixing bowl, whisk together all-purpose flour, baking powder, baking soda, cinnamon, nutmeg, and salt.

In another bowl, combine granulated sugar, brown sugar, and vegetable oil. Blend until smooth, then add eggs one at a time.

Slowly add the dry ingredient mixture to the wet ingredients, mixing just until combined.

Fold in the grated carrots, drained crushed pineapple, and shredded coconut if using.

Divide the batter between prepared pans. Bake for 30-35 minutes for round pans or 40-45 minutes for a 9x13 pan.

Remove the pans from the oven and cool for 10-15 minutes before transferring to a wire rack.

In a mixing bowl, beat together softened cream cheese and unsalted butter, then gradually mix in powdered sugar, vanilla extract, and milk or pineapple juice.

Frost the cooled cake layers generously with the frosting.