Use a 6-quart slow cooker. Place the drained pears into the slow cooker. Add the entire bottle of wine and stir in the sugar, taking care to not break up the pear halves. Add the vanilla and float the cinnamon stick and the star anise pods on top.

Cover and cook on low for 5 hours or on high for 2 hours. Serve warm with a big dollop of whipped cream.