Preparing the Blackberries

1. Wash and Drain: Rinse the blackberries under cold water and let them drain in a colander. Pat them dry gently with a paper towel to remove excess moisture.
2. Sweeten and Flavor: In a mixing bowl, toss the blackberries with granulated sugar and lemon juice until evenly coated. Set aside while you prepare the cobbler topping.

Making the Cobbler Topping

1. Mix Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt until well combined.
2. Incorporate Butter: Add the cold, cubed butter to the flour mixture. Using a pastry cutter or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs.
3. Add Liquid: Pour the boiling water and milk over the flour mixture and stir until just combined. The dough will be sticky and shaggy, but that’s perfectly fine.

Assembling and Baking

1. Preheat the Oven: Set your oven to 375°F (190°C) and grease a 9×13-inch baking dish.
2. Layer the Berries: Spread the sweetened blackberries evenly in the bottom of the prepared baking dish.
3. Top with Dough: Using a spoon or your hands, drop spoonfuls of the cobbler dough over the blackberries, covering them as much as possible.
4. Bake to Perfection: Place the assembled cobbler in the preheated oven and bake for 35-40 minutes, or until the topping is golden brown and the blackberries are bubbling.