Cut a circle of parchment paper slightly smaller than base of large pot; set aside.

Using paring knife, cut vanilla in half lengthwise; scrape seeds out and scrape in same pot. Add sugar and using hands rub vanilla seeds. Add orange zest, star anise, (if using)ginger, cinnamon stick and 6 cups water to boil over medium-high heat until sugar dissolves.

Meanwhile, peel pears, leaving stems intact. Using ½ tsp measure, core each pear through bottom.

Reduce heat to simmer. Add pears; place parchment circle over top, pressing directly on pears. Place plate over paper to keep pears submerged for even cooking. Return to simmer; cook until tender in centre when pierced with knife, 15 to 20 minutes. Remove from heat; let pears cool in syrup for 1 hour.

Using slotted spoon, transfer pear to serving bowl. Remove the spices and reduce the poaching liquid over medium heat to 1 ½ cups; drizzle some of the syrup over top.