Preheat the oven to 375°F and lightly grease a 9x13-inch baking dish and set aside.
In a large bowl, mix together the pears, cranberries, sugar, tapioca flour (or cornstarch), orange zest, cinnamon, and juice.
Stir until evenly combined, then spread the fruit mixture into the prepared baking dish.
In a separate medium bowl, whisk together the flour, baking powder, salt, granulated sugar, and brown sugar for the crumble topping.
Add the melted butter and stir until small clumps form.
Sprinkle the crumble topping evenly over the fruit mixture.
Bake for 45-50 minutes, until the fruit is bubbly and the topping turns golden brown.
Allow the crumble to rest for 15 minutes before serving, so the filling can thicken.
Enjoy warm with vanilla ice cream.