Preheat oven to 350 degrees.
Grease and flour 3 8" round cake pans. I like to line my pans with parchment paper. (optional)
Sift all dry ingredients. Set aside.
In the bowl of a stand mixer, mix together oil, sugar, eggs-beaten after each addition until smooth and combined.
Add the dry ingredients to the wet mixture a little at a time, beating on medium speed, until well combined. Scrape down the sides of the bowl to make sure everything is combined well.
Add carrots, pineapple, and nuts. Beat on medium until just combined. You can also fold this in by hand if you like. Mix well.
Pour the batter evenly into the prepared cake pans and bake for 30-35 minutes or until a toothpick inserted in the middle comes out clean. Start checking after 30 minutes.
Remove the pans from the oven and cool on a wire rack until they have cooled completely. Level the tops of the cakes if you like. Frost.