In a medium bowl, cube the cored and peeled pears into the lemon juice, tossing as you go to prevent browning.
Stir the pears into dry mixture well and add the vanilla.
Pour into an unbaked 24cm deepdish pie shell.
Cover with lattice top, or top of your choice. Tuck top edge under bottom edge, pinch/flute edge all the way around well to seal.
Brush top with a little water very lightly, and optionally sprinkle the top with cinnamon sugar.
Bake at 220°C for 15 minutes then reduce the heat to 175°C and bake for another 45-50 minutes. Watch for any excessive browning on edges, may need to cover them lightly with foil.