Begin by preheating your oven to 350°F (175°C) and greasing a 9x13 inch baking pan.

In a medium bowl, whisk together all-purpose flour, baking powder, baking soda, salt, ground cinnamon, ground nutmeg, and ground ginger.

In a large mixing bowl, beat together softened unsalted butter, granulated sugar, and brown sugar until light and fluffy. Add eggs one at a time, mixing well, and then stir in the vanilla extract.

Slowly fold in the dry ingredients, followed by the grated carrots, crushed pineapple, and chopped walnuts (if using).

Pour the batter into the prepared pan and bake for 30-35 minutes or until a toothpick comes out clean.

In a mixing bowl, beat together softened cream cheese and unsalted butter until smooth. Gradually add powdered sugar and stir in vanilla extract.

Once the cake has cooled completely, spread the cream cheese frosting over the top, then cut into squares and serve.