Preheat oven to 400°F. Lightly grease a 2-quart baking dish and set aside.
Place frozen peaches in a colander under cold running water until thawed. Pat dry with paper towels and discard excess liquid. (If using fresh, wash, peel and slice peaches.)
32 ounces frozen sliced peaches, thawed
In a medium saucepan, combine the peaches, both sugars, cinnamon, lemon juice, and vanilla.
¼ cup white sugar, ¼ cup light brown sugar, ½ teaspoon ground cinnamon, 2 teaspoons lemon juice, ½ teaspoon vanilla extract
Cook over medium heat for 5-7 minutes until bubbling. Stir in the cornstarch and cook 1-2 more minutes until thickened. Pour into the prepared baking dish.
1 tablespoon cornstarch
In a large bowl, whisk together flour, sugars, baking powder, and salt. Cut in the cold butter using a pastry cutter or fingertips until the mixture resembles coarse crumbs. Pour in the milk and stir just until combined — avoid overmixing.
1½ cups all-purpose flour, ¼ cup white sugar, ¼ cup light brown sugar, 1½ teaspoons baking powder, ½ teaspoon salt, 8 tablespoons unsalted butter, ⅓ cup cold milk
Drop spoonfuls of the topping evenly over the warm peach filling, leaving small gaps for steam to escape. Bake for 35-40 minutes, or until the topping is golden and the filling is bubbling at the edges.
Allow the cobbler to cool for 10-15 minutes before serving. Delicious on its own or topped with a scoop of vanilla ice cream.