Preheat your oven to 375°F (190°C). This ensures that the cobbler bakes evenly and the topping becomes golden brown.

In a mixing bowl, combine the blueberries, ½ cup of sugar, flour, lemon zest, lemon juice, and salt. Gently toss to coat the blueberries without crushing them.

Pour the blueberry mixture into a greased 9-inch baking dish, spreading it evenly across the bottom.

In a separate bowl, whisk together the flour, baking powder, salt, and remaining ¼ cup of sugar. This helps to evenly distribute the leavening agent and sweetener.

Add the cold, cubed butter to the flour mixture. Using a pastry cutter or your fingers, work the butter into the flour until the mixture resembles coarse crumbs. This step is crucial for a flaky topping.

Pour in the milk and stir until just combined. Do not overmix; a few lumps are okay. This will keep the biscuit topping light and tender.

Drop spoonfuls of the biscuit batter over the blueberry filling, leaving some gaps for the filling to bubble up during baking.

Place the baking dish in the preheated oven and bake for 30-35 minutes, or until the biscuit topping is golden brown and the filling is bubbling around the edges.

Once baked, remove from the oven and let it cool for about 10 minutes before serving. This allows the filling to set slightly, making it easier to serve.