Preheat the oven to 375F and place your baking rack on the lower middle position.
For the Filling
In a 9-inch pie pan, mix the sugar, cornstarch, cinnamon and salt with a fork. Add the blueberries and turn over to coat. Add the lemon zest and lemon juice and stir with a spatula until combined. Bake for 25 minutes.
For the topping
While the blueberries re baking, prepare the cobbler topping. Whisk the flour, sugar, cornmeal, baking soda, baking powder, and salt in a large bowl.
Whisk the buttermilk,melted butter, and vanilla in a small bowl.
Stir together the cinnamon and sugar and set aside.
When the blueberries are done, remove from the oven and increase the oven temperature to 425F.
Mix the buttermilk into the flour mixture and stir to combine. Divide the dough into eight parts using a tablespoon or a cookie scoop and place them on to the cooked blueberries. Leave some space between dough ball and don't let it touch the sides of the pan. Sprinkle the dough with the cinnamon sugar.
Bake for an additional 15- 18 minutes. The blueberries will be bubbling and the biscuits will be golden brown on top.
Remove from the oven and let cool on a wire rack for 20 minutes. Serve warm with a scoop or two of ice cream.