8tablespoons (1 stick) cold, unsalted butter, cut into small pieces
1teaspoon vanilla extract
1/2cup whole milk
1tablespoon turbinado sugar
Whipped cream (optional)
Combine blackberries and granulated sugar. Let stand at least 30 minutes.
Preheat oven to 400F. Line a baking sheet with parchment.
Combine flour, pecans, brown sugar, baking powder and salt in a large mixing bowl. Add butter and using your fingers or a fork, cut butter into the flour mixture until it resembles coarse meal. Add vanilla and milk.
On a lightly floured cutting board, pat dough into a 5 x 9-inch rectangle, 3/4-inch thick. Cut into 8 pieces. Sprinkle turbinado sugar on top.
Place shortcakes on a baking sheet and bake 15 to 18 minutes, until puffed and lightly colored. Cool on a wire rack.
Slice shortcakes into halves horizontally; spoon blackberries and juice between halves and top with whipped cream, if using.