Place all ingredients in a small saucepan, ensuring that all the pears are completely covered with liquid.
Cut a circular piece of parchment paper that fits inside the 8- or 9-inch (20- or 23-cm) spring-form pan to keep pears from being exposed to air (if the pears are not covered with something—liquid or parchment—they will brown).
Bring heat to a simmer, and let poach in liquid for about 30 minutes or until soft—not mushy.
Remove pears from liquid, and bring remaining liquid to a boil.
Reduce heat to a simmer, and allow to reduce by ½ to ¾, or until liquid is nice and syrupy.
Remove cinnamon stick and pour syrup over pears and garnish with a sprinkle of cinnamon and/or some orange zest to serve.