Beat together the oil, white sugar, brown sugar, eggs and vanilla until smooth.
Whisk together the flour, cinnamon, baking powder, baking soda and salt. Beat the flour mixture with the wet mixture until smooth and there are no clumps.
Fold the grated carrots, pineapple and nuts into the batter.
Pour the batter into the 13x9 pan.
Bake in oven for about 1 hour or until a toothpick inserted in the centre of the cake comes out clean.
Remove from he oven and cool on a wire rack.
Make the cream cheese frosting by beating together the cream cheese and butter. Beat in the icing sugar, a little at a time, until all incorporated and the frosting has a smooth consistency. Beat in the vanilla.