Preheat your oven to 375°F (190°C) and lightly grease your baking dish.
In a mixing bowl, gently toss the blueberries with sugar and lemon juice until evenly coated. The mixture should look juicy and vibrant.
Pour the blueberry filling into your prepared baking dish, spreading it out evenly. You should see the juices beginning to pool and the berries nestled together.
In a separate bowl, combine the flour, sugar, cinnamon, and salt. Add the cold butter pieces and use a pastry cutter or your fingers to blend until the mixture resembles coarse crumbs.
Sprinkle the crumb mixture evenly over the blueberry filling, covering it completely with a rustic, crumbly topping.
Bake in the preheated oven for 40-45 minutes, or until the topping is golden brown and the filling is bubbling around the edges. You’ll hear that satisfying crackle as the juices simmer and burst.
Remove the cobbler from the oven and let it cool slightly before serving. The top should be crisp, and the filling bubbly and thick.