Tested and perfected, I can say with no hesitation that this is the best blueberry cobbler you’ll ever make! It pairs a jammy fresh berry filling with a fantastic, moist buttermilk cobbler topping.
Preheat oven to 350°F. Lightly grease an 10 x 7-inch glass baking dish with nonstick spray or butter (see note).
In prepared pan, make the filling by tossing together blueberries, cornstarch, 2 tablespoons granulated sugar, and lemon juice, until the blueberries are evenly coated.
In medium-sized bowl, whisk together the flour, granulated sugar, baking powder, and salt. Add the diced butter to the dry ingredients. Use a pastry cutter, fork, or your fingers to work the butter into the flour mixture until it resembles coarse crumbs and sticks together when you press it with your fingertips.
1 cup all-purpose flour, ½ cup granulated sugar, 1 teaspoon baking powder, ¼ teaspoon salt, 6 tablespoons unsalted butter, cold and diced
Stir the buttermilk and vanilla extract into the dry mixture until dough comes together. It will be sticky and resemble biscuit dough.
⅓ cup buttermilk, 1 teaspoon vanilla extract
Drop spoonfuls of the dough over the blueberry mixture, leaving some gaps for the filling to bubble through. It does not have to be smooth on top. The dough will spread as it bakes. Sprinkle the top with coarse sugar, if desired.
1 tablespoon coarse sugar for optional topping
Bake in preheated oven 50 to 55 minutes, or until the topping is golden brown and the blueberry filling is bubbling.
Let the cobbler cool for 20 to 30 minutes before serving. Scoop onto serving plates or shallow bowls. Enjoy warm or at room temperature with vanilla ice cream or whipped cream, if desired.
Notes
Baking dish: We recommend a glass baking dish or white ceramic dish for this recipe. The size should be comparable to 10 x 7 inches (77 square in.); a 9 inch square pan (81 square in.) will work.
Using frozen blueberries: If your blueberries are frozen, put the frozen berries into the baking dish, mix with sugar, cornstarch, and lemon juice, and microwave on high power for 5 minutes. Proceed with recipe as directed. We tested this a number of times, and without this step, the topping remains partly uncooked in the middle due to the frozen berries.
Buttermilk: Regular milk can be substituted for buttermilk. We tested the recipe both ways and slightly preferred the flavor of buttermilk but there’s not a huge difference.