Preheat oven to 350 degrees. Grease and flour a 8x12 inch pan. 
In a medium bowl sift together flour, baking soda, salt and cinnamon.  Set aside.  

In a large bowl, combine eggs, buttermilk, oil, sugar and vanilla. Mix well. Add flour and mix well.   

In medium bowl combine shredded carrots, coconut and walnuts. Using a large wooden spoon, add carrot mixture to batter and fold n well. Pour half into prepared 8x12 inch pan and other half in another pan and bake at 350 degrees for 45 minutes. Check with toothpick. Allow to cool for at least 20 minutes before serving. 

Using the cream cheese frosting recipe for middle and top.