Beat butter and shortening at medium speed with an electric mixer until fluffy; gradually add sugar, beating well. Add egg yolks, 1 at a time, beating until blended after each addition. Add vanilla, beating until blended.
Combine flour and soda; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed until blended after each addition. Stir in coconut.
Beat egg whites until stiff peaks form, and fold into batter. Pour batter into 3 greased and floured 9-inch round cakepans.
Bake at 350° for 25 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks 10 minutes; remove from pans, and cool completely on wire racks.
Spread Nutty Cream Cheese Frosting between layers and on top and sides of cake. Garnish, if desired.
Make twice and each time...delicious and perfect! Hints: double the frosting, dust your pans w/powdered sugar vs flour. Since cake is large and requires refrigeration...carry it in a large cooler...so your folks don't have to make room for it in their already crowded holiday fridge. Don't worry...it won't last long!
I took this to a dinner party and everyone raved about it. I did add 2/3 cup of pecans to the batter, and made extra frosting. Left nuts out of some of the frosting and trimmed out the cake with the plain frosting and added a ring of whole pecans around the top edge. Great presentation & exceptional taste. Will make again & again.