Heat oven to 350°F. Grease and flour 12-cup fluted tube pan or 10-inch tube pan.
Beat butter, sugar and vanilla in large bowl until fluffy. Add eggs; beat well. Stir together flour, l teaspoon baking soda and salt; add alternately with buttermilk to butter mixture, beating until well blended.
Measure 2 cups batter in small bowl; stir in syrup and remaining 1/4 teaspoon baking soda. Add coconut, if desired, to remaining vanilla batter; pour into prepared pan. Pour chocolate batter over vanilla batter in pan; do not mix.
Bake 60 to 70 minutes or until wooden pick inserted in center comes out clean. Cool l5 minutes; remove from pan to wire rack. Cool completely; glaze or frost as desired. Makes 12 servings.
* To sour milk: Use 1 tablespoon white vinegar plus milk to equal 1 cup.