Step 1: Preheat your oven to 375°F (190°C). Lightly butter a 9x13 inch baking dish.
Step 2: In a large bowl, gently toss the fresh or frozen blueberries with 1/2 cup granulated sugar, 2 tablespoons all-purpose flour, 1 tablespoon lemon juice, and 1 teaspoon lemon zest.
Step 3: Pour the blueberry mixture evenly into the prepared baking dish.
Step 4: In a separate medium bowl, whisk together the self-rising flour, 1/4 cup granulated sugar, and 1/2 teaspoon ground cinnamon (if using). Cut in 1/2 cup cold butter, cubed, using a pastry blender, two knives, or your fingertips, until the mixture resembles coarse crumbs.
Step 5: Gradually add 1/2 cup milk to the flour mixture, stirring just until combined. Do not overmix.
Step 6: Drop spoonfuls of the cobbler topping over the blueberry filling, distributing as evenly as possible.
Step 7: Sprinkle 1 tablespoon of granulated sugar evenly over the top of the cobbler topping.
Step 8: Bake for 40-50 minutes, or until the topping is golden brown and the blueberry filling is bubbly and thick. If the topping browns too quickly, loosely tent with foil. Let cool for at least 15-20 minutes before serving.