Add flour, cocoa powder, baking powder, salt, and sugar to a bowl and mix to combine.
In a separate bowl, combine milk, egg, oil, and espresso powder.
Combine wet mixture into dry and thoroughly mix, then add chopped white chocolate.
Grease the Mini Waffle Maker with butter or a small amount of non-aerosol cooking oil. Add ¼ cup of batter into preheated Mini Waffle Maker and cook until the waffle is cooked through (around 3 minutes). Remove and let cool.
