Gather all ingredients.
Preheat the oven to 425 degrees F (220 degrees C).
Combine peaches, ¼ cup white sugar, ¼ cup brown sugar, ¼ teaspoon cinnamon, nutmeg, lemon juice, and cornstarch in a large bowl; toss to coat evenly, and pour into a 2-quart baking dish. Bake in preheated oven for 10 minutes.
Meanwhile, combine flour, ¼ cup white sugar, ¼ cup brown sugar, baking powder, and salt in a large bowl. Blend in butter with your fingertips or a pastry blender until mixture resembles coarse meal. Stir in water until just combined.
Remove peaches from oven, and drop spoonfuls of topping over them.
Mix 3 tablespoons white sugar and 1 teaspoon cinnamon together in a small bowl; sprinkle over entire cobbler.
Bake in the preheated oven until topping is golden, about 30 minutes.
