Spray 3 (9-inch) round pans with cooking spray; cover bottoms with waxed paper. Add boiling water to chocolate in small bowl; stir until chocolate is completely melted.
Beat egg whites in small bowl with mixer on high speed until stiff peaks form; set aside. Mix flour, baking soda and salt. Beat butter and sugar in large bowl with mixer until light and fluffy. Blend in egg yolks, 1 at a time. Add melted chocolate and vanilla; mix well. Beat in flour mixture alternately with buttermilk, mixing well after each addition. Gently stir in egg whites until well blended.
Pour into prepared pans.
Bake 35 min. or until toothpick inserted in centers comes out clean. Immediately run spatula around cakes. Cool in pans 15 min. Remove cakes from pans to wire racks; remove waxed paper. Cool cakes completely. Meanwhile, prepare Coconut-Pecan Filling and Frosting.
Stack cakes on plate, filling layers and spreading top of cake with frosting. (Note: Nutrition is for both cake and frosting.)
This classic 3-layer cake is the perfect choice for a special occasion. Plan ahead and eat accordingly before indulging in a slice of this beloved cake.
Substitute unsifted 1-3/4 cups all-purpose flour for the sifted cake flour.
Cake can be prepared in the following alternate baking pans: For 1 (13x9-inch) pan, bake 45 to 50 min. or until toothpick inserted in center comes out clean; for 2 (8-1/2-inch) heart-shaped pans, bake 30 to 35 min. In high-altitude areas, use 1-3/4 cups plus 2 Tbsp. all-purpose flour and 1 cup plus 1 Tbsp. sugar. For 2 (9-inch) layer pans, bake at 375°F for 30 to 35 min. or until toothpick inserted in centers comes out clean. For 1 (13x9-inch) pan, bake 40 min. or until toothpick inserted in center comes out clean.
* Percent Daily Values are based on a 2,000 calorie diet.
* Nutrition information is estimated based on the ingredients and cooking instructions as described in each recipe and is intended to be used for informational purposes only. Please note that nutrition details may vary based on methods of preparation, origin and freshness of ingredients used.