For the Filling:

8 cups blueberries, rinsed

1/3 to 1/2 cup sugar, depending on the sweetness of the fruit

2 tablespoons lemon juice

For the Topping:

1 cup cornmeal

3/4 cup all-purpose flour

1/2 cup sugar

2 1/2 teaspoons baking powder

1/4 teaspoon ground cinnamon

1/4 teaspoon salt

3/4 cup buttermilk

6 tablespoons unsalted butter, melted and cooled

1 egg, slightly beaten

FOR THE FILLING:
Heat the oven to 375 degrees F.
Toss the blueberries with the sugar and lemon juice. Pour into a 13-by-9-inch oval baking dish.
 

FOR THE TOPPING:
Combine the cornmeal, flour, sugar, baking powder, cinnamon, and salt in a mixing bowl. Make a well in the center and pour in the buttermilk, melted butter, and beaten egg. Stir with a wooden spoon to blend and then mix with a fork only until the batter comes together.

Drop the batter by spoonfuls on top of the blueberries in the pan. Bake the cobbler for 40 to 45 min, or until the filling is bubbly and the topping is firm when pressed.