Preheat to 350 degrees.
Prepare pans by buttering and flouring. Additionally, you might want to use parchment paper to line pans.
Cream butter for two minutes
Add sugar, and cream for two more minutes.
Add egg yolks, one at a time, incorporating each yolk fully
Mix together and sift, flour, baking powder, baking soda and salt.
Add flour mixture and buttermilk to sugar/butter mixture in stages, beginning and ending with flour mixture. Add in coconut (optional).
Prepare egg whites, by beating with electric whisker until foamy. Add in cream of tarter and beat until soft peaks are formed.
Incorporate egg whites into cake batter, gently, so as not to deflate. Immediately place into prepared pans.
You can use 2 pans or three pans for either a 4 layer or 3 layer cake. If making a four-layer cake, use serrated knife to cut each cake in two.
Bake at 350 for 25-35 minutes, depending on how many layers you use. Three layers will take less time.