Preheat the oven to 350 degrees. In a small bowl, combine the first four ingredients in the Fruit Filling section and set aside. Place the butter In a 2 quart baking dish and place it in the oven to melt the butter. In a medium bowl combine the flour, 3/4 cup granulated sugar, baking powder, salt and cinnamon. In a small bowl combine the milk and vanilla. Add this mixture to the flour mixture. Mix until moist. Remove the baking dish from the oven. Spread the batter on top of the butter. The melted butter will peek up around the edges a bit. Layer the blackberry mix on top of the batter. Press the blackberries down into the batter a bit. Bake for 45 minutes. Sprinkle with the coarse sugar and bake for 5-10 more minutes or until the batter has reached a beautiful golden brown.