Preheat the oven to 375 F and butter a 9”x13” rectangular baking dish.
In a medium sauce pan bring the water, 3/4 cups sugar, cinnamon, and butter to a boil over medium heat. Stir occasionally. After the mixture has come to a boil, stir in the vanilla and remove pan from heat.
In a large mixing bowl stir together Bisquick, milk, ¼ cup sugar and melted butter to form a dough.
Sprinkle a bit of extra Bisquick unto some parchment paper. Roll the dough out into a 10"x14" rectangle. Cover the dough with the fresh blackberries leaving a 1” border on one long side. Roll into a log like cinnamon rolls.
Cut the log into 8 slices and arrange in the buttered baking dish.
Pour hot syrup over the rolls and bake at 375 F for 25 - 35 minutes until dough is cooked through. The edges will become golden.
Serve hot or at room temperature with ice cream or whipped cream as desired.