In a large bowl, combine blueberries, 0.5 cup sugar, 0.25 cup flour, lemon juice, and cinnamon. Toss gently to coat. Pour the blueberry mixture into a 9x13 inch baking dish.
In a separate medium bowl, whisk together 1.5 cups flour, 0.75 cup sugar, baking powder, and salt.
Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs.
Pour in the milk and stir until just combined. Do not overmix.
Drop spoonfuls of the topping mixture over the blueberries, covering most of the surface.
Bake for 35-40 minutes, or until the topping is golden brown and the blueberry filling is bubbly.
Let cool for at least 15 minutes before serving. Serve warm, with ice cream or whipped cream if desired.
Notes
This cobbler is best served warm. If you have leftovers, they can be stored in the refrigerator for up to 3 days. Reheat gently in the oven or microwave.