1) In the refrigerator, chill the pears.
2) Beat together the cream and vinegar till the mixture is thick without being too stiff.
3) Add salt, sugar and freshly ground pepper to season to taste.
4) Peel the pears and cut them in half. Scoop out the cores with the help of a teaspoon.
5) On individual small plates, serve the pars rounded side up with the tarragon cream spooned all over them.