combine berries and cinnamon in a 9 x 13 baking dish. Combine flour, 3/4 c. sugar, and baking powder in a mixing bowl and stir. Add milk and melted butter while stirring dry ingredients. Pour/drop batter mixture over the berries trying to cover all.
combine cornstarch and 1/2 C sugar in a small mixing bowl and stir. Sprinkle mix over the entire pan. Remove boiling water from stove and slowly pour over the entire pan. Place the baking dish in the oven and bake for 45-50 minutes or until crust is golden. Some areas may appear whitish due to the sugar mix. Make sure top crust is nice and crispy, remove from oven and cool slightly. Serve warm