Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.

In another bowl, mix the vegetable oil, granulated sugar, brown sugar, and eggs until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the grated carrots, chopped walnuts, and vanilla extract.

Divide the batter evenly between the prepared cake pans.

Bake in the preheated oven for 30-40 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

Once cooled, frost with cream cheese frosting if desired and serve.