01 - Combine water, sugar, fresh ginger slices, and lemon juice in a large saucepan. Place over medium heat and bring to a gentle simmer, stirring occasionally until sugar completely dissolves.
02 - Add prepared pear halves to the simmering syrup. Cut a parchment paper circle to fit the saucepan and place directly on top to keep pears submerged during cooking.
03 - Maintain a gentle simmer for 20 to 25 minutes until pears are tender when pierced with a knife but still hold their shape. Avoid boiling vigorously to prevent breaking.
04 - Using a slotted spoon, carefully transfer pear halves to a plate or serving dish. Set aside while finishing the syrup.
05 - Add finely chopped candied ginger to the remaining syrup. Continue simmering uncovered for 5 to 10 minutes until syrup slightly reduces and intensifies in flavor.
06 - Remove saucepan from heat. Discard the fresh ginger slices from the syrup using a slotted spoon or strainer.
07 - Arrange pear halves on serving plates. Spoon warm ginger syrup generously over each portion. Sprinkle with chopped pistachios and additional candied ginger if using. Serve warm or refrigerate to serve chilled.