Beat the parfait in a planet mixer until light and airy and add the pastis and the finely chopped tarragon. Pipe into the desired moulds using a piping bag and store in the freezer.
For the orange crème, bring the crème brûlée to the boil and add the orange purée. Transfer to a suitable container and store in the refrigerator.
Finishing touch
Remove the semifreddos from the moulds and arrange on the plates. Finish the dish with the orange crème, orange segments, chocolate decoration, Atsina Cress and sprigs of tarragon.