Allow your waffle iron to preheat according to manufacturers directions. Preheat oven to 200 degrees F and lay a wire rack inside of a baking sheet.
In a large bowl, whisk the flour, baking soda, baking powder, salt, and sugar together.
In another bowl, whisk together the eggs, butter, and buttermilk.
Stir egg mixture into the dry ingredients, without overworking. Let rest for 5 minutes.
Grease the waffle iron with the spray (if required), portion out waffle batter (I use a 1/3 cup scoop for my waffle maker), close and cook until crispy and golden on both sides (they should easily come out of the waffle maker).
Arrange waffles on wire rack and place in oven to keep warm as you work through the batter.