Peel the pears with a vegetable peeler and half each one neatly from top to bottom to attain 8 halves. Remove the cores and any tough fibres – I use a melon-baller for this exercise, though a sharp teaspoon also works. Place the pears into a heavy saucepan into which they fit quite snugly. Peel 4 thin strips off the lemon and add to the pears along with all of the juice from the lemon. Sprinkle on the caster sugar and the lightly crushed cardamom pods. Cover with a sheet of parchment paper and a tight fitting lid and cook over a very low heat until the pears are tender. This takes about 30 minutes but the time will vary according to the ripeness of the pears used. Allow the cooked pears to cool completely. These pears can be cooked a day ahead and refrigerated.
Place the chocolate in a small Pyrex bowl and sit the bowl over a saucepan of cold water. The bottom of the Pyrex bowl must not be touching the water in the saucepan. Turn on the heat and as soon as the water comes to the boil, turn off the heat. The chocolate will not be fully melted but will continue to melt perfectly in the residual heat. Do not allow the chocolate to get cold.
Drain the pears from the cooking juices and pat dry. Place in a single layer in a flat serving dish. I arrange them in cartwheel fashion with the thinner tops of the pears pointing toward the centre of the plate.
Add the oil to the chocolate and mix well. Using a dessertspoon, drape chocolate to cover each pear either completely or partially. Straightaway sprinkle each pear with cocoa nibs, chopped pistachios and diced candied orange peel. Put the pears to sit in a cool place or in the fridge to allow the chocolate to set slightly. The pears will sit happily like this for several hours.
Serve the pears with a little of the cooking juices poured around them and some softly whipped cream.