In a medium bowl, sift flour, sugar, baking powder, and salt. Set aside.
In a separate small mixing bowl, whisk egg, milk, and melted butter until combined.
Add wet ingredients to the dry and mix until just combined.
Grease the mini waffle maker with butter or a light coating of cooking oil.
Pour 3-4 tablespoons of batter into the mini waffle maker and cook until golden brown, about 3-4 minutes. Repeat with remaining batter.