Combine cranberries, ginger, cinnamon stick and 2 cups of water in a medium saucepan. Bring the mixture to a simmer, lower the heat to medium-low and simmer for 10 minutes.
Remove ginger and cinnamon stick and set aside.
Strain the cranberry mixture into another saucepan, pressing down on the solids to extract all liquid -- you should have about 2 cups of liquid.
Return the reserved ginger and cinnamon stick to the cranberry juice. Add the pear juice/ cider, sugar and vanilla bean. This is a great time to check the taste and adjust the taste by adding more juice or sugar.
Bring the mixture to a simmer and reduce the heat to medium-low and simmer for 10 minutes.
Remove the ginger and cinnamon stick and vanilla bean. Add the diced pears (if using) and remove from heat. Serve warm.