1/2 cup granulated sugar
1 tablespoon cornstarch
pinch ground cinnamon
pinch table salt
6 cups fresh blueberries
1 1/2 teaspoons grated lemon zest
1 tablespoon lemon juice
1 cup unbleached all-purpose flour
2 tablespoons cornmeal , stone-ground
1/4 cup granulated sugar , plus 2 teaspoons for sprinkling
2 teaspoons baking powder
1/4 teaspoon baking soda
1/4 teaspoon table salt
4 tablespoons unsalted butter (1/2 stick), melted
1/3 cup buttermilk
1/2 teaspoon vanilla extract
1/8 teaspoon ground cinnamon
Adjust oven rack to lower-middle position and heat oven to 375 degrees.
Stir sugar, cornstarch, cinnamon, and salt together in large bowl.
Add berries and mix gently with rubber spatula until evenly coated; add lemon zest and juice and mix to combine.
Transfer berry mixture to 9-inch glass pie pan, place pie pan on rimmed baking sheet, and bake until filling is hot and bubbling around edges, about 25 minutes.
Whisk flour, cornmeal, 1/4 cup sugar, baking powder, baking soda, and salt in large bowl to combine.
Whisk melted butter, buttermilk, and vanilla in small bowl.
Mix remaining 2 teaspoons sugar and cinnamon in second small bowl and set aside.
One minute before berries come out of the oven, add wet ingredients to dry ingredients; stir with rubber spatula until just combined and no dry pockets remain.
Remove berries from oven; increase oven temperature to 425 degrees.
Pinch off 8 equal-sized pieces biscuit dough and place on hot berry filling, spacing them at least 1/2 inch apart (they should not touch). Sprinkle each mound of dough with cinnamon-sugar.
Bake until filling is bubbling and biscuits are golden brown on top and cooked through, 15 to 18 minutes.
Cool cobbler on wire rack 20 minutes and serve