Combine the dry ingredients (flour, sugar, baking powder, salt, and cocoa) in a large bowl. Make a well in the middle of the ingredients and set this bowl aside.
Separate the eggs. In a medium bowl, use an electric hand mixer to beat the egg whites until they make a meringue (creamy white and fluffy).
In another bowl, mix the egg yolks, milk, melted butter, and vanilla. Fold in the whipped egg white, leaving it lumpy.
Add the egg mixture into the well in the dry ingredients and mix together with a rubber spatula just until combined. You want the batter to still be a little lumpy.
Add in the chocolate chips.
Use a ladle to pour the batter into a preheated waffle maker. Cook the waffles until crisp.
They are best served hot with whipped cream, syrup, and fresh berries.