Step 1: Preheat your oven to 350°F (175°C) and grease and flour three 9-inch round cake pans.
Step 2: In a large bowl, cream together the butter, shortening, and sugar until light and fluffy. Add the egg yolks one at a time, beating well after each addition. Stir in the vanilla.
Step 3: Combine the flour and baking soda. Add to the creamed mixture alternately with the buttermilk, beginning and ending with the flour mixture.
Step 4: Stir in the shredded coconut and 1 cup of toasted pecans until evenly distributed.
Step 5: In a separate clean bowl, beat the 5 egg whites until stiff peaks form. Gently fold the egg whites into the cake batter until no white streaks remain.
Step 6: Divide the batter evenly between the prepared pans. Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Step 7: Cool the cakes in the pans for 10 minutes before removing them to wire racks to cool completely.
Step 8: To make the frosting, beat the cream cheese and 1/2 cup butter until smooth. Gradually add powdered sugar and vanilla, beating until creamy. Frost between layers and over the top and sides of the cake. Garnish with remaining pecans.