Turn the oven to 350°F (180°C).
Butter or spray an 8x12-inch (20 x 30 cm) rectangular pan. You can line it with a wide strip of parchment paper, covering the bottom and the two long sides. It will aid when removing the cake.
In a large bowl, beat 1 cup vegetable oil, 1 cup brown sugar, ½ cup white sugar and 2 eggs for 2 minutes.
Add the sifted dry ingredients (2 ½ cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt½ teaspoon ground cinnamon and ¼ teaspoon ground ginger) and mix just until blended.
Add 2 cups grated carrot, 1 cup crushed canned pineapple and 1 ½ teaspoons vanilla extract. Mix with a spatula until everything is well integrated without dry parts but don't overdo it.
Fold in ¾ cup chopped walnuts.
Pour cake batter in the prepared cake pan and smooth the top.
Bake for 45-50 minutes, or until a cake tester or toothpick comes out dry.
Let cool on a wire rack and run a smooth-bladed knife around the edge to loosen any parts that might be stuck.
Remove from the pan, using the parchment paper as an aid when lifting the cake. Let cool completely.
Transfer to the serving plate and spread the cream cheese frosting on top. Sprinkle with ½ cup chopped walnuts if wanted.