Mix the flour with the butter and salt, using a fork or your fingers.
Add the water and knead further until the dough is homogeneous.
Roll the dough into a ball and cut it in two. Set one part aside, in the fridge or freezer, for another time.
Let the dough for the tart rest in the fridge for half an hour, until the butter has hardened again.
Half an hour later
Preheat the oven to 180 °C.
Roll out the dough on a floured surface. The shape doesn't need to be lined: it's a 'keep it simple' tart.
Place a sheet of baking paper on the oven rack and slide the dough onto it.
Slice the pear (with skin and core!) into very thin slices, using a slicer or a sharp kitchen knife.
Arrange the slices on the dough, sprinkle some cane sugar over it, and slide it into the oven.
Bake for 13 minutes. For the last 5 minutes, set the oven to extra heat from below, so the dough bakes thoroughly.