Step 1
Preheat oven to 350 degrees F.
Step 2
Whisk together the flour, salt, baking powder, baking soda, cinnamon, and ginger in a mixing bowl for a minute or two; reserve until needed.
Step 3
In another mixing bowl, combine the sugar, oil, and eggs. Whisk until thoroughly combined. Whisk in the melted butter. Use a spatula to stir in the carrots, pineapple, and nuts. Stir in the flour mixture in two additions.
Step 4
Scrape the batter into a lightly greased 13 x 9 baking dish. Bake for about 40 minutes, or until the top springs back slightly when gently touched with your finger. Remove and allow to cool completely before frosting.
Step 5
To make the frosting: Use an electric mixer to beat together the butter, cream cheese, milk, and vanilla until light and fluffy. Gradually beat in the powdered sugar to form a smooth frosting. Spread evenly over the cooled cake.