Preheat oven to 400°F and line a baking sheet with parchment paper or a silicone baking mat.
In a mixing bowl, stir together the flour, baking powder and salt.
Stir in the yogurt and melted butter.
The dough should be shaggy and moist. Different yogurts have different moisture content, so an extra tablespoon or two of flour or yogurt may be needed at this point.
Scoop about 3 Tablespoons of dough onto the prepared baking sheet. Sprinkle with sugar if desired.