Ingredients:

  • 6 cups fresh blackberries (approx. 750g)
  • 3/4 cup granulated sugar (150g)
  • 2 tablespoons cornstarch (16g)
  • 1 large lemon, zested and juiced
  • 1/2 teaspoon ground cinnamon
  • 1/4 teaspoon fine sea salt
  • 2 cups all-purpose flour (250g)
  • 1/4 cup granulated sugar (50g)
  • 1 tablespoon baking powder
  • 1/2 cup cold unsalted butter (113g), cubed and chilled
  • 3/4 cup cold buttermilk (180ml)
  • 1 teaspoon vanilla extract
  • 1 large egg
  • 1 tablespoon water
  • 1 tablespoon granulated sugar for sprinkling

Instructions:

  1. Preheat your oven to 375°F (190°C) and prepare a 9x13 inch (3-quart) ceramic or glass baking dish.
  2. In the baking dish, combine fresh blackberries, 3/4 cup sugar, cornstarch, lemon juice, lemon zest, cinnamon, and salt. Toss gently to combine without crushing the fruit.
  3. Allow the berry mixture to macerate for 10 minutes. This allows the sugar to draw out juices to properly hydrate the cornstarch starch granules.
  4. In a large mixing bowl, whisk together the all-purpose flour, 1/4 cup sugar, and baking powder.
  5. Using a pastry cutter or two forks, work the cold, cubed butter into the flour mixture until it resembles coarse meal with some pea-sized chunks remaining for lamination.
  6. Stir in the cold buttermilk and vanilla extract until a shaggy dough forms. Do not overmix.
  7. Drop spoonfuls of dough or cut biscuit rounds over the blackberry filling. Brush the tops with egg wash (1 egg beaten with 1 tablespoon water) and sprinkle with the remaining tablespoon of sugar.
  8. Bake for 45 minutes until the filling is bubbling and the biscuit topping is a deep mahogany brown and cooked through.