Spray a 9 by 13 inch baking dish with cooking spray. Add the blueberries, 2/3 cup sugar, lemon juice, and cinnamon. Stir to combine well. Set aside and let rest.
In a mixing bowl whisk together the flour, baking powder, and salt. Set aside.
Using a stand mixer or a hand mixer, beat together the room temperature butter and 3/4 cup granulated sugar. Beat until light and fluffy.
Beat in the milk, then the egg, and then the vanilla.
Add the flour mixture and beat until just combined. The dough batter will be very sticky.
Add the blueberry mixture to the bottom of the prepared baking dish.
Drop the dough on top. Bake for 50 to 60 minutes or until the dough is golden brown. Remove from the oven. Let sit until no longer hot, but still warm (20 to 30 minutes) and serve with vanilla ice cream.
You can use fresh blueberries in this recipe, but keep in mind that will shorten the cooking time. At the 30 minute mark, keep an eye on your cobbler to make sure the crust doesn't get overcooked.