Set your oven to 180 degrees. Butter the souffle plates that have a half glass of water capacity. Mix the rest of the butter with sugar and yolk and whisk them until they bubble. Add the orange peel grater, baking powder and sifted flour slowly. Whisk the pineapple juice and the milk. Add the mix with the egg slowly. Take a pinch of salt and gently add it and eggwhite to the mix. Place the mix in the plates. Put them in the oven and let them heat for 30-35 minutes. Sprinkle the powder sugar lastly and serve them nicely. Enjoy!