Preheat the oven to 110C/225F/Gas ¼. Line two baking sheets with baking parchment.
Slice the pears really thinly into rounds using a mandolin or a very sharp knife.
Lay the pears in a single layer on the baking parchment. It doesn’t matter if you have to squeeze the rounds to fit them all onto the paper as they shrink as they dry out.
Stir together the sugar and ginger, then sprinkle liberally over each piece. Bake in the oven for three hours, turning over halfway through.
Remove the pear crisps from the oven and let them cool.
Collect the remaining sugar dusting from the baking sheet and add a little extra sugar to suit. Shake the gingery sugar over the pear crisps.