Preheat oven to 375 degrees.

Sifted together, sugar, cornstarch, & cinnamon into a medium bowl. Whisk the mixture making sure the mixture is fully combined. Add blueberries, with your fingers toss to coat & set aside.

Add flour, baking powder, sugar, salt in a food processor bowl and pulse until combined. Add butter and pulse until mixture resembles coarse oatmeal. Transfer mixture to a large bowl, and add heavy cream and vanilla in a steady stream, mixing with a spatula until the dough comes together. Using your fingers, gather the dough and divide into 9 equal pieces, and loosely form each piece into a ball and flatten to about ½-inch thickness. Set aside.

Transfer blueberry mixture to a greased 8-inch square-baking dish. Top blueberry mixture with cobbler dough balls, spacing evenly. Brush dough with heavy cream, & sprinkle with coarse sugar or granulated sugar. Bake until berries are bubbling in center & dough toppings are golden brown, about 50-55 min. Transfer dish to a wire rack, & let cool slightly, about 30-40 min.