1. Preheat oven to 425 degrees.
2. Prepare a 9"x13" baking dish with butter or shortening.
3. In a large bowl, stir together the filling for the cobbler: peaches, sugar, brown sugar, cinnamon, lemon juice, and cornstarch.
4. Spoon the peach mixture evenly to the baking dish.
5. Bake uncovered for 10 minutes.
6. As the peaches cook, combine flour, sugar, brown sugar, baking powder, and salt in a food processor.
7. Add the butter, pulsing until the mixture resembles sand. Add the water and pulse until the dough comes together into a smooth paste.
7. Using oven mitts, carefully remove the baking dish from the oven.
8. Add dollops of the dough mixture over the peaches as evenly as possible.
9. In a small bowl, stir together the cinnamon topping and sprinkle evenly over the dough.
10. Place the cobbler back in the oven and bake for 25 to 30 minutes or until the topping is golden brown and the peaches are bubbling.
11. Cool a few minutes before serving.