In a large bowl, whisk together the flour, baking powder and salt.
In a medium bowl, whisk together the Greek yogurt, eggs, melted butter, and milk. Add the wet ingredients to the dry and stir thoroughly to combine.
Let batter rest for 10 minutes (don't skip this step!)
Warm the waffle iron and when it is ready, scoop ¼ cup of the batter and place in the center of the waffle iron. Close lid and cook until done.
Repeat with the remaining batter to finish the batch; you may need to add a bit of milk if the batter becomes very thick. Waffles may be frozen or stored in the fridge for up to 5 days.