• Preheat your oven to 350°F. Place 4 tablespoons of butter into a 9x13 inch baking dish and place it in the oven so that the butter can melt (this should take about 5-7 minutes). 
• While that is in the oven, add your cake mix to a large bowl, then add in the cornmeal and stir it in with the cake mix until fully combined. 
• Now mix the buttermilk into the cake batter and stir it in until it is fully incorporated. Remove the baking dish from the oven and swirl the melted butter all around the dish so that it evenly coats the whole pan.
• Now spray the entire dish with non-stick cooking spray. Gently pour the cobbler batter that you just prepared into the baking dish.

Prepare the blueberries: 

• Add your blueberries to a large bowl and gently mash some of them down with the back of a large spoon.
• Now sprinkle in half of the granulated sugar, the vanilla extract and the cinnamon. Stir everything together until the blueberries are fully coated.
• Now dollop spoonfuls of the blueberry mixture onto the cobbler batter. Sprinkle the rest of the sugar over the top of the cobbler.
• Place the baking dish in the oven and bake for about 45-55 minutes, until the cobbler crust is golden brown and the blueberries are nice and bubbly.
• Remove it from the oven and allow it to cool down for about 7-10 minutes before serving. Serve with vanilla ice cream or your favorite whipped topping. And enjoy!