3/4 cup all-purpose flour
2 tablespoons unsweetened cocoa powder
4 ounces bittersweet or semisweet chocolate, chopped
3 tablespoons unsalted butter, plus more for brushing waffle iron
1/2 cup sugar
2 large eggs, beaten
Vanilla ice cream, whipped cream, caramel sauce, sprinkles and maraschino cherries, for topping
Special equipment: waffle iron (preferably Belgian style)
Preheat a waffle iron to medium-high. Preheat the oven to 200 degrees F (to keep cooked waffles warm). Sift together the flour, cocoa powder and 1/8 teaspoon salt in a small bowl; set aside.
Combine half the chocolate and the butter in a medium saucepan over medium heat, stirring until melted and smooth, about 5 minutes. Remove from the heat and let cool slightly. Stir in the sugar and eggs. Add the flour mixture and remaining chocolate and stir until just combined.
Lightly brush the top and bottom of the waffle iron with butter. Fill the waffle iron about three-quarters of the way full (some waffle iron should still be showing). Close the lid gently and cook until the waffles are cooked through and slightly crispy around the edges, 4 to 6 minutes. Keep the cooked waffles warm in a 200 degrees F oven or covered with foil on a plate while you make the remaining waffles.
Top each waffle with ice cream, whipped cream, caramel sauce, sprinkles and a cherry, if desired.