Sift together flour, cocoa powder, baking soda and salt onto sheet of waxed paper.
Beat butter and sugar in bowl until smooth and creamy. Beat in eggs, one at a time. Beat in vanilla. Beat in flour mixture alternately with buttermilk, beginning and ending with flour mixture.
Make waffles in waffle maker following manufacturers directions. Make twelve 4-inch waffles (6 double Belgian waffles); stack between sheets of waxed paper on baking sheet; keep warm in 225°F oven.
Serve with ice cream and 2 tablespoons syrup per serving; pass the extra syrup.
Combine bittersweet chocolate, heavy cream and strong black coffee in small, heavy saucepan. Heat over low heat, stirring, until chocolate is completely melted and mixture is smooth.