01 - 
                Set oven to 350°F (175°C).
              
              
              
                02 - 
                Mix together oil or applesauce, sugar, and eggs in a big bowl.
              
              
              
                03 - 
                Add flour, baking soda, baking powder, salt, and cinnamon and stir until everything's mixed.
              
              
              
                04 - 
                Gently add carrots, coconut, nuts (if you're using them), vanilla, and pineapple with its juice.
              
              
              
                05 - 
                Pour your mixture into a 10x15-inch jelly roll pan that's lightly greased or lined with parchment.
              
              
              
                06 - 
                Bake for about 25-30 minutes. It's done when you stick a toothpick in the middle and it comes out clean. Let it cool all the way.
              
              
              
                07 - 
                Whip butter and cream cheese till they're light and fluffy. Then add vanilla and powdered sugar, mixing until it's smooth.
              
              
              
                08 - 
                Put the frosting all over the cooled cake bars in an even layer.
              
              
              
                09 - 
                Put any leftovers in the fridge in a sealed container. They'll stay good for up to 3 days.