Slice starfruit crosswise into star shapes and drain on paper towel.
Chop pistachio nuts into small pieces.
Dip half of the starfruit slice into your favorite dark chocolate sauce (thick enough to adhere to the fruit).*
Quickly sprinkle finely chopped pistachio nuts on the chocolate and let the whole thing dry on a cooling rack.
* Use a tall cup with an opening just wide enough to fit a starfruit slice.