In a large bowl combine the flour, yeast, sugar and salt. In a separate bowl, whisk together the milk, coffee, eggs, butter and vanilla. Stir into the dry ingredient mixture, stirring just enough to blend. Cover with plastic wrap and allow to sit in a warm place until doubled in size, about 45 minutes.
Fold in the chocolate chips. Preheat the waffle iron according to the manufacturer's instructions. Spoon in enough of the batter to cover the iron. Bake until done and golden brown. Serve hot with Maple Coffee Butter.
Serves 4