Prepare coconut: Preheat oven to 350°F Take coconuts and drain milk (drill or tap holes in two of the three "eyes" and drain milk). Place in preheated oven 20 - 30 minutes (or until they crack). Remove from oven and allow to cool slightly. Take a flat-head screwdriver and pry shell off of meat. Next, taking a vegetable peeler, peel the brown outer layer from coconut. Next, peel a few long strips for garnish and set aside, if desired. Cut coconut into manageable pieces. Shred coconut either by hand or with a food processor, using a fine shredding blade. Place flaked coconut in two bowls, equally (around 3 cups per coconut, a little more or less is okay).
Mix milk, sugar, butter, egg yolks and vanilla in large saucepan. Cook on medium heat approximately 12 minutes until thickened and golden brown, stirring constantly (just as mixture starts to boil). Remove from heat.
Add flaked coconut (from ONE coconut) and pecans; mix well. Let sit for 2-3 hours (overnight is okay) to achieve a "raw honey"-like texture. Frost as directed below.
Note: Reserve the remaining coconut for finishing the cake.
Line bottoms of 3 (9-inch) round cake pans with wax paper (cut 3 sheets of waxed paper from box; place all 3 on bottom of cake pan; take back side of butter knife and rub around the edge of the pan creating a crease; cut out circles on crease); butter sides of pan.
Microwave chocolate and water in large microwavable bowl on HIGH 1-1/2 to 2 minutes or until chocolate is almost melted, stirring after each minute. Stir until chocolate is completely melted.
Preheat oven to 350°F.
Beat egg whites (4) with whisk attachment in mixer until stiff peaks form. Remove to separate bowl.
In mixer, combine butter and sugar on medium speed until light and fluffy. Add egg yolks, 1 at a time, beating well after each addition. Stir in cooled chocolate mixture (if hot, it will "cook" the eggs) and vanilla. Add flour, baking soda and salt. add buttermilk slowly, beating until well blended. Gently fold egg whites into batter.
Pour evenly into prepared pans, making sure batter is evenly distributed (batter is SLIGHTLY thicker in middle than around sides).
Bake for 20-30 minutes or until toothpick inserted into centers comes out clean (do NOT over-bake, as this will result in a dry cake). Immediately run spatula between cakes and sides of pans. Cool 15 minutes; remove cake layers from pans. Remove wax paper. Cool completely on wire racks.
Take sharp serrated knife and gently go around top of each cake, cutting away excess cake so that it has a flat top. Place one cake UPSIDE DOWN on a 9" cake round.
Spread coconut-pecan filling and frosting between layers and onto top of cake. Taking your hand, scoop up some frosting and press into side of cake until covered (this is the messy part!). Then take some of the extra coconut and secure the frosting by pressing it into the sides of the cake (you will probably have extra coconut). Pat around cake twice until you receive a nice finished product. Transfer cake (with cake round) onto a pretty round plate, if desired.
Garnish suggestions: Use whole pecans and coconut on top. Coconut curls may be created by shaving a strip of coconut, cutting it into 1/4" slices then securing it around a straw with butcher's twine (or other type of thick string) until dry.
Serving Suggestion: Place mini chocolate morsels around cake. Serve with natural vanilla ice cream.