Combine the Shiraz, orange juice and sugar in a heavy-based saucepan and warm gently over a medium heat until the sugar is dissolved. Add the orange zest, star anise and cinnamon stick.
Add the pears and bring to the boil. Immediately reduce the heat to a low simmer and cook for up to 1 hour, turning every now and then, until the pears are tender but not too soft. The cooking time can vary considerably depending on the ripeness of the pears so be sure to check often for doneness.
Remove the pears and set aside. Remove the orange zest and spices and reserve the spices for garnish if desired. Boil the syrup for about 10 minutes, stirring occasionally, until thickened. Pour the syrup over the pears and cool at room temperature for 10 minutes, then cover and chill for a few hours in the fridge.Before serving, drizzle the pears with the syrup and serve with a dollop of mascarpone.