Place the wine, peppercorns, vanilla beans, zest, cardamom and sugar in a 2 1/2-quart saucepan and cook over medium-high heat, stirring occasionally, until the sugar is dissolved. Bring the saucepan to a boil then reduce to a gentle simmer. Place the pears in the saucepan and cook for about 30 to 45 minutes, or until the pears are tender.
Remove the pears from the poaching liquid and set aside on a plate. Allow them to cool completely.
While the pears are cooling, strain the poaching liquid and discard solids. Return the liquid to the pan, increase the heat to medium-high and reduce the poaching liquid to a syrup, about 5 to 10 minutes. You should have about 1/2 cup syrup. Set aside.
When the pears are cool enough to handle, remove the inner core using a melon baller. Stuff each pear with 2 tablespoons of the mascarpone.
To serve, pour about 2 tablespoons of the poaching syrup on a chilled appetizer plate with a pear in the center. Sprinkle toasted pistachios around the plate and garnish with mint leaves and orange zest. Drizzle with creme anglaise, if desired.