FOR THE VANILLA BATTER: Cream butter, sugar and vanilla in large mixer bowl until light and fluffy. Add eggs; beat well. Combine flour, 1 teaspoon baking soda and the salt; add alternately with buttermilk to creamed mixture.
FOR THE CHOCOLATE BATTER: Combine syrup and 1/4 teaspoon baking soda. Measure 2 cups of the vanilla batter into small bowl; blend in chocolate syrup mixture.
Add coconut to remaining vanilla batter; pour vanilla batter into GREASED and FLOURED 12 cup Bundt pan or 10 inch tube pan. Pour chocolate batter over vanilla batter in pan; DO NOT MIX.
Bake at 350°F about 70 minutes or until cake tester comes out clean. Cool 15 minutes; remove from pan. Cool completely; glaze or frost as desired. I served it plain with whipped cream. 12 to 16 servings.
TO MAKE THE ICING: Cream butter and confectioners’ sugar in small mixer bowl; blend in syrup. Melt chocolate bar pieces in top of double boiler over hot, not boiling, water; add to syrup mixture. Add milk; beat to spreading consistency. Makes about 2 1/2 cups.
TO MAKE THE GLAZE: Combine chocolate and cream in small saucepan. Cook over very low heat, stirring constantly, until chocolate is melted and mixture is smooth; do not boil. Remove from heat; cool, stirring occasionally, until mixture begins to thicken, about 10 to 15 minutes. About 1 cup.
TO MAKE CHOCOLATE-COCONUT FROSTING: Combine sugar and cornstarch in small saucepan; blend in evaporated milk. Cook over medium heat, stirring constantly, until mixture boils; remove from heat. Add chocolate bar pieces and butter; stir until chocolate is melted and mixture is smooth. Stir in coconut and nuts. Immediately spread on cake. About 2 cups frosting.
*To sour milk: Use 1 Tablespoon vinegar plus milk to equal 1 cup.
**You may substitute 1 1/3 cups semi sweet chocolate chips for the baking chocolate.