Preheat the oven to 350 degrees F. Spray three 9-inch cake pans with nonstick flour spray.
In a large bowl, beat the sugar and butter at medium speed with a mixer until fluffy. Add the egg yolks, coconut extract and vanilla extract, beating until combined. In a medium bowl, combine the flour, baking powder, baking soda and salt.
In a small bowl, combine the coconut milk and buttermilk. Gradually add the flour mixture to the butter mixture alternately with the coconut milk mixture, beginning and ending with the flour mixture, beating just until combined after each addition.
In a medium bowl, beat the egg whites until stiff peaks form. Gently fold into the batter. Spoon the batter into the prepared cake pans and bake for 18 minutes. Let cool.
Spread the Luscious Lime Frosting between the layers and on the top and sides of the cake. Press coconut flakes around the cake. Garnish with fresh raspberries and lime slices, if desired. Chill until ready to serve.
In a large bowl, beat the butter, lime juice and lime zest at medium speed with a mixer until combined. Gradually add the confectioners' sugar, beating until smooth. Add the whipped topping, beating until combined.