For The Cake, Place A Rack In The Center Of The Oven, And Preheat The Oven To 325°F.
Grease And Flour Three 9″ Round Cake Pans.
Shake Out The Excess Flour, And Set The Pans Aside.
Place The Butter And Shortening In A Large Mixing Bowl, And Blend With An Electric Mixer On High Speed Until Creamy, 1 Minute.
Gradually Add The Sugar, Blending On Medium Speed.
Add The Egg Yolks, One At A Time, Beating Just Until Combined.
Add The Vanilla And Combine.
Sift The Flour And Baking Soda In A Small Bowl, And Sift To Combine Well.
Spoon A Third Of The Flour Mixture Into The Butter Mixture And Blend On Low, Then Add ½ Cup Of The Buttermilk And Blend.
Add Another Third Of The Flour Mixture, Then The Rest Of The Buttermilk, Blending, Then The Rest Of The Flour Mixture.
Fold In The Coconut And Pecans Just Until Combined.
Set Aside.
Place The 5 Egg Whites In A Large Mixing Bowl, And Beat With Clean Beaters On High Speed Until Stiff Peaks Form, 4 Minutes.
Fold The Beaten Whites Into The Batter Until The Whites Are Well Combined.
Divide The Batter Between The 3 Pans, And Smooth The Tops.
Place The Pans In The Oven.
Bake Until The Cakes Are Golden Brown And Just Pull Away From The Sides Of The Pans, 22 To 25 Minutes.
Remove The Pans To A Wire Rack To Cool For 10 Minutes, Then Run A Knife Around The Edges.
Shake The Layers Gently, Then Invert Onto The Rack Right Side Up To Cool Completely, 30 Minutes.
Leave The Oven On.
Meanwhile, Make The Frosting.
Place The ¼ Cup Nuts In A Small Pan In The Oven To Toast For 3 To 4 Minutes.
Remove And Set Aside To Cool.
Place The Butter And Cream Cheese In A Large Mixing Bowl, And Beat With An Electric Mixer On Medium Speed Until Creamy, 1 Minute.
Add The Vanilla And Half Of The Confectioners’ Sugar, Beating On Medium Until Combined.
Add Another Cup Of Sugar And The Salt And Blend On Medium-High Until Combined And Light.
Add The Remaining Sugar As Needed, And Beat On Medium-High To Lighten The Frosting.
Fold In The Cooled Toasted Nuts.
To Assemble The Cake, Place 1 Cooled Layer On A Cake Stand And Cover With ¾ Cup Of Frosting, Spread To The Edges.
Place A Second Layer On Top, And Spread It With ¾ Cup Of Frosting.
Place The Third Layer On Top, And Add 1 To 1½ Cups Frosting To The Top Of The Cake, Spreading It Decoratively Across The Top.
Use The Remaining Frosting To Frost The Sides Of The Cake, Using Smooth, Clean Strokes.
Pat Extra Coconut On Top Of The Cake For Garnish, If Desired.
