Preheat oven to 350°F and butter a 9x13-inch baking dish.
In a large bowl, toss together pears, cranberries, 3/4 cup sugar, orange zest, orange juice, and cornstarch. Transfer to prepared baking dish.
In a medium bowl, whisk together flour, remaining 1/4 cup sugar, baking powder, salt, and cinnamon. Cut in cold butter until mixture resembles coarse meal.
Stir in milk and vanilla extract until just combined. Drop large spoonfuls of batter evenly over the fruit mixture.
Bake for 45-50 minutes until the topping is golden brown and the fruit filling is bubbling.
Allow to cool for 10-15 minutes before serving.