Preheat a Belgium waffle maker. In a large bowl mix the flour, cocoa powder, sugar, baking powder, and salt. Melt the butter and set aside to cool a little.
Beat the eggs, vanilla extract, and water in a small bowl. Whisk the egg mixture into the dry mixture, then quickly mix in the melted butter. Finally stir in the chocolate chips.
Spray the waffle iron with non-stick cooking spray. Pour one-third of the batter into the waffle iron, close and cook for approximately 3 minutes. Lift the lid to check the waffle. It should be fully formed, but soft to the touch. Carefully turn the waffle iron to flip the waffle out. The moment it starts cooling, it will crisp up. Repeat with the remaining batter.
Serve as-is, with powdered sugar on top, or "a la mode" with vanilla ice cream and chocolate sauce!