Resift flour, baking powder, sugar & salt into mixing bowl. Beat together in another small bowl eggs, vanilla, milk & orange juice. Gradually pour liquid ingredients into flour & stir with wooden spoon to blend well. Gently stir in grated orange rind. Do not overwork batter; it should remain a little lumpy.
Finally, stir in melted butter, cover, & put aside for at least l hour. Heat waffle iron. Scrape batter into pitcher & when iron is ready, pour in enough batter to cover 2/3 of iron's surface. Close the cover & bake until most of steam has stopped escaping from around sides of the iron. Remove baked waffles at once.