Combine all ingredients but pears in a large saucepan. Bring mixture to a boil and cook for 5 minutes. Add pears and cover with a parchment round. Reduce to a simmer and cook until pears are tender, 20 to 30 minutes. If necessary, turn pears very gently by rotating the stems with your fingertips so they cook evenly. Remove pears to a bowl, bring poaching liquid to a rapid boil, and reduce by half, about 10 minutes.
Pour reduced syrup over pears and refrigerate, covered, for at least 6 hours, preferably overnight. Serve in shallow bowls or cups.