Great dessert for a dinner party because you can make the pears a few days in advance.
Pour the Riesling into a medium saucepan and whisk in the sugar until it dissolves.
Peel the pears, leaving stem intact, if present. Remove bottom stem end with a small melon baller, and continue to scoop up into the pear to remove the core. Place the pears right in the Riesling mixture (poaching liquid) after they are peeled and cored to prevent them from discoloring. (The acidity of the wine keeps them from browning). Add just enough water to cover the pears.
To keep the pears submerged in the poaching liquid, cut a circle of parchment paper the size of the pan and lay on the surface of the liquid. Place a small plate on top of the paper to make sure the pears are completely submerged. Cook the pears over medium-high heat, just until the liquid comes to a boil. Reduce the heat to low and poach the pears until they are just soft. The pears should be tender enough to pierce with a knife. This takes about 20 to 25 minutes for ripe medium pears, but this can vary depending on the size, variety and ripeness of the pear.
Remove the pan from the heat and cool the fruit completely in the poaching liquid. Refrigerate the fruit in the liquid in a sealed container until ready to serve. (The fruit will hold for 4 to 5 days, the longer the fruit is stored in the poaching liquid, the fuller the flavor).
Pour about half of the poaching liquid into a skillet and bring to a boil over high heat. Continue to cook and reduce until the liquid gets syrupy and about the consistency of honey.
Meanwhile, whip the cream together with the sugar and cardamom until cream just holds soft peaks. Refrigerate until ready to serve.
To serve, place a pear in a bowl or on a plate. Drizzle with reduced Riesling syrup and garnish with a dollop of whipped cream.