Lightly grease an 8-inch-square baking dish. Place the blueberries into the baking dish and mix with vanilla and lemon juice. Sprinkle with 1/2-cup of sugar and ½ teaspoon of flour; then stir in the tablespoon of melted butter. Set aside. In a medium bowl, stir together 1¾ cups of flour, baking powder, and 6 tablespoons of sugar. Rub in the 5 tablespoons butter using your fingers or cut in with a pastry blender until it is in small pieces. Make a well in the center and quickly stir in the milk. Mix just until moistened. You should have a very thick batter, or a very wet dough. You may need to add a splash more milk. Cover, and let batter rest for 10 min.

Preheat the oven to 375 degrees. Spoon the batter over the blueberries, leaving only a few small holes for the berries to peek through. Mix together the cinnamon and 2 teaspoons sugar; sprinkle over the top. Bake for 20-25 minutes in the preheated oven, or until the top is golden brown. A knife inserted into the topping should come out clean – of course there will be blueberry syrup on the knife. Let cool until just warm before serving. This can be stored in the refrigerator for two days.