With a potato peeler, peel the pears very carefully removing only the skin but leaving the stalk on. Using a melon-baller, scope out and remove the core from each pear forming a small cavity to place the ganache inside.
In a stainless steel saucepan, bring the poaching liquid to the boil, add the pears and poach gently for 5 to 6 minutes. Remove from the heat and leave the pears to cool in their own liquid. When cool drain and put to one side.
For the Chocolate ganache
Bring the cream to the boil, remove from the heat and gently stir in the chocolate and butter. Add the brandy, pour into a plastic container and refrigerate for at least 2-3 hours.
For the Caramel Sauce
Bring to the boil the poaching liquid and reduce until it starts to caramelise. Add the fresh ginger and remove from the heat. Carefully add the calvados, mix well and strain through a fine sieve. Chill.
Roll each pear in the mixed pistachio crumbs and brown sugar, covering evenly. Fill the cavity of each pear with chocolate ganache and place them on a greased baking sheet.
Roast the pears in a hot oven (180ºc/350ºf) for 4-5 minutes. Remove and carefully place in the middle of 4 serving plates. Serve with ginger caramel sauce and vanilla ice cream.