Preheat oven to 350 degrees F. Spray 13×9 in pan with non-stick cooking spray. Set aside. For cake, whisk together flour, baking soda, cinnamon and salt in a medium bowl. Set aside.

Place eggs, buttermilk, vegetable oil, vanilla extract, and sugar in a large bowl and mix until smooth. Slowly add in dry ingredients and mix until just combined. Gently fold in carrots, coconut, and pineapple. Pour batter evenly into prepared pan and bake 35 to 40 minutes or until cake springs back when pressed.

While the cake is baking prepare the glaze. Add sugar, buttermilk, butter, corn syrup and baking soda to medium sized saucepan over medium eat. Vigorously stir mixture for about 8 minutes. The glaze with turn a light amber color. Remove from heat and stir in vanilla extract. Set aside until ready to use.

When the cake comes out of the oven, immediately poke holes in cake. Pour the buttermilk glaze evenly over the top of the hot cake. Let cake cool completely.

For the frosting mix together cream cheese and butter until light and fluffy. Add brown sugar, cinnamon and vanilla extract and mix until combined. Slowly add powdered sugar and mix until smooth. Spread evenly over cooled cake.