Preheat oven to 350ºF. Pile pears into an 8x8" glass baking dish and toss with the cinnamon. In a medium bowl, combine the topping ingredients using your fingers to squeeze it all together until no dry flour remains. Sprinkle evenly over the pears. Bake in centre of oven until filling is bubbling at the edges, about 50 minutes, tenting with aluminium foil if topping is browning too quickly.
Notes
*I don't use any sugar in the filling because pears are so naturally sweet they truly jam up to sweet deliciousness without any.