Preheat your oven to 350°F and coat a 9×13" baking dish with cooking spray.
Arrange the drained pear slices in a single layer in the dish.
Sprinkle sugar and cinnamon evenly over the pears.
Evenly dust the cake mix over the spiced pears without stirring.
Drizzle melted butter and reserved pear juice over the cake mix until it resembles sandy crumbs.
Bake for 45 minutes, until the top is golden and you see gentle bubbling around the edges.
Let the cobbler rest 10 minutes before serving.
Notes
On my initial trial, I learned that neatly arranging pear slices helps the syrup spread evenly under the topping.By the third bake, drizzling melted butter slowly around the pan prevented soggy spots and kept the topping crisp.When freezing leftovers, I found wrapping individual portions sealed with plastic wrap stopped syrup separation during thawing.