In a large bowl, combine the blueberries, sugar, lemon juice, cornstarch, cinnamon (if using), and vanilla extract. Stir gently to coat the berries evenly.
Transfer the blueberry mixture into a greased 9-inch baking dish (or similar size). Set aside while you prepare the topping.
2. Make the Cobbler Topping:
In a medium bowl, whisk together the flour, sugar, baking powder, and salt.
Add the cold, cubed butter to the dry ingredients. Using a pastry cutter or your hands, work the butter into the flour mixture until it resembles coarse crumbs with pea-sized pieces of butter.
Pour in the milk and vanilla extract, stirring gently until just combined. The dough will be thick and slightly lumpy—don’t overmix.
3. Assemble the Cobbler:
Spoon dollops of the cobbler dough evenly over the blueberry filling. It doesn’t need to cover the filling completely, as the dough will spread as it bakes. For a more rustic look, you can drop spoonfuls randomly over the top.
Sprinkle the coarse sugar over the cobbler topping to create a sweet, crunchy crust.
4. Bake the Cobbler:
Bake in the preheated oven for 35-45 minutes, or until the topping is golden brown and the blueberry filling is bubbling around the edges. A toothpick inserted into the topping should come out clean (though a little blueberry juice might cling to it).
5. Serve:
Let the cobbler cool for about 10-15 minutes before serving to allow the filling to set slightly.
Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream for extra indulgence.
