Preheat your oven to 350°F (175°C) and grease and flour two 9-inch round cake pans.
In a large bowl, combine the sugar, brown sugar, flour, pumpkin pie spice, baking powder, baking soda, and salt. Mix these dry ingredients together, and then set the bowl aside.
In a medium-sized bowl, whisk together the vegetable oil, eggs, and vanilla until they are well combined. Then, add the grated carrots, crushed pineapple, and any optional ingredients like chopped toasted walnuts or raisins if you're using them. Stir everything together until it's evenly mixed.
Now, pour the liquid mixture from the medium bowl into the large bowl with the dry ingredients. Use a spatula or a wooden spoon to gently stir everything together. Be careful not to overmix; just stir until you can't see any more flour spots. This will ensure your cake stays moist and fluffy.
Evenly distribute the cake batter into the prepared cake pans and use a spatula to smooth the tops.
Place the pans in the preheated oven and bake for about 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
Once the cakes are done, remove them from the oven and allow them to cool in the pans for about 10 minutes. Then, transfer the cakes to a wire rack to cool completely.
