01 - In a large saucepan, combine water, sugar, vanilla bean or extract, orange zest and juice, lemon zest and juice, and cinnamon stick if using. Bring to a gentle simmer over medium heat, stirring until the sugar dissolves completely.
02 - Add the peeled and cored pear halves to the simmering liquid. Cover with a round of parchment paper to keep pears submerged during cooking.
03 - Maintain a gentle simmer for 20 to 30 minutes, or until pears are tender when pierced with a knife but still hold their shape.
04 - Using a slotted spoon, carefully transfer the pear halves to a serving dish and set aside.
05 - Increase the heat to high and boil the poaching liquid for 5 to 10 minutes until slightly reduced and syrupy in consistency.
06 - Strain the syrup if desired, then pour over the reserved pears. Serve warm, at room temperature, or chilled, with the syrup spooned generously over each portion.