Rebekah's Blackberry Ginger Cobbler

Finally made after years of Dad bugging me for a blackberry cobbler...

Filling: 

36 oz. fresh blackberries

1 1/4 cups white sugar

1/4 cup cornstarch

1/4 tsp. ground cinnamon

1 tsp. (ore more) fresh grated ginger

pinch of salt

Biscuit Topping:

2 cups all-purpose flour

1 T. white sugar

2 tsp. baking powder

1/2 tsp. baking soda

1 tsp. kosher salt (or 1/2 tsp. table salt)

1 cup buttermilk, chilled

8 T. unsalted butter, melted + 3 T. extra for drizzling

1 T. turbinado sugar

Preheat oven to 375 degrees. Grease a 9x13" baking dish. Place blackberries, 1 1/4 cups sugar, cornstarch, cinnamon, ginger, and salt in baking dish and mix until all sugar is wet and well incorporated. Place in oven and bake until starting to bubble, about 30 minutes. Meanwhile, mix together flour, 1 T. sugar, baking powder, baking soda, and salt in a large mixing bowl. Melt 8 T. butter and allow to cool for about 10 minutes. Pour butter into a bowl with the cold buttermilk, then mix gently until butter hardens into lots of little chunks throughout the buttermilk. Pour buttermilk mixture into flour mixture and mix with a spatula just until incorporated, with some dry flour still showing. Keep refrigerated until ready to use. When berries start to bubble, remove pan from oven and evenly drop biscuit dough all over the top of the berries. Melt remaining 3 T. butter and drizzle all over top of dough. Sprinkle with turbinado sugar. Return to oven and bake until top is golden brown, about another 20 minutes. Serve warm, preferably with fresh whipped cream fortified with sour cream!