Preheat oven to 350 degrees.
In large bowl beat butter and shortening with mixer until combined. Add sugar, beat on medium high speed till mix is light and fluffy. Add egg yolks and vanilla, beat well. In another bowl combine flour, baking powder, baking soda; add to egg yolk mixture alternating with buttermilk, beating until just combined after each addition. Stir in coconut and 1 cup chopped pecans.
In a small bowl, beat egg whites until stiff peaks form. Stir about 1/3 of the whites into cake batter to lighten. Fold in remaining whites.
Pour batter evenly into 3 greased and floured 8" cake pans. Bake for 25 to 30 minutes or until toothpick inserted in the center comes out clean. Cool in pans 10 minutes, remove from pans and cool thoroughly on wire racks.
Spread with icing. Decorate with pecan halves. Keep chilled until serving time and store leftovers in the refrigerator.
***NOTE*** If you are as lazy as me, you can bake this cake in a greased and floured 13x9x2" baking pan. Bake 35 to 40 minutes or until toothpick inserted in the center comes out clean. Frost with 1/2 recipe of Cream Cheese Frosting. Not as impressive looking as a stately 3 layer cake---but---much easier and just as darn tasty!!******
Cream Cheese Frosting:
In a small mixing bowl beat cream cheese, butter, and vanilla until smooth. Gradually add powdered sugar, beating until smooth. Stir in 1/2 cup chopped pecans. pecans.. Makes 2 cups of frosting.