Preheat your conventional oven to 175 degrees Celsius carefully. Grease your three round cake pans with butter thoroughly. Line the bottoms with round parchment paper circles cleanly.
Whisk your flour, sugars, baking soda, and cinnamon together. Ensure all dry ingredients blend evenly in a large bowl.
Beat your vegetable oil and fresh eggs in another bowl. Pour the wet mixture into your dry ingredients slowly. Stir gently until a thick batter forms completely.
Fold your shredded carrots and crushed pineapple into the batter. Toss in your chopped walnuts using a rubber spatula. Mix gently until everything spreads out evenly.
Divide your cake batter among the three prepared pans. Tap the pans on the counter to remove bubbles. Bake them in the oven for thirty-five minutes.
Check the centers with a clean wooden toothpick carefully. The toothpick should come out clean with no wet batter. Let the layers cool in pans for ten minutes.
Invert the pans onto your wire cooling racks gently. Peel off the parchment paper circles slowly. Let the cake layers cool down completely before frosting.
Place your soft cream cheese and butter into a bowl. Beat them with your electric mixer until fluffy. Add the powdered sugar slowly until smooth.
Place your first cake layer onto a serving plate. Spread a thick layer of frosting across the top. Stack the second layer on top carefully.
Repeat the frosting process for the final cake layer. Cover the top and sides of the cake completely. Press extra walnuts onto the sides if you like.