Step 1: Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.
Step 2: In a large bowl, cream together the 1/2 cup butter, shortening, and granulated sugar until light and fluffy.
Step 3: Add the egg yolks one at a time, beating well after each addition. Stir in the vanilla extract.
Step 4: In a separate bowl, whisk together the flour and baking soda. Add to the creamed mixture alternately with the buttermilk, beginning and ending with the flour.
Step 5: Stir in the shredded coconut and 1/2 cup toasted pecans.
Step 6: In another clean bowl, beat the egg whites until stiff peaks form. Gently fold the whites into the cake batter until just combined.
Step 7: 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 8: Allow the cakes to cool in the pans for 10 minutes before removing them to wire racks to cool completely.
Step 9: For the frosting, beat the cream cheese and butter until smooth. Gradually add powdered sugar and vanilla, beating until creamy.
Step 10: Frost between the layers and over the top and sides of the cake. Garnish with remaining pecans.