Sweet, buttery, tender rustic shortcakes overflowing with sweet local blackberries, and lightly sweetened whipped cream. These rustic blackberry shortcakes are bursting seasonal flavor.
Set a rack in the center of the oven; heat to 400 degrees. Line a baking sheet with parchment or lightly grease. Set aside
Using a box grater, grate partially frozen butter onto a plate. Spread grated butter around the plate and return to the freezer. In a large bowl, whisk the flour, baking powder, salt, sugar, lemon zest, and nutmeg. Sprinkle chilled, grated butter over flour mixture and gently toss with your hands to coat the butter with the flour mixture. Using a fork gently stir in the buttermilk until the dough just holds together with no large, dry lumps.
Spoon the dough onto the baking sheet in six equal mounds. Brush the tops with buttermilk; sprinkle with sugar. Bake until the peaks have begun to brown and the bottoms are golden, 20 to 25 minutes. Let rest for 1 minute and then transfer to a wire rack. While still slightly warm, slice them open with a serrated knife.
Set aside 2 cups of the berries. In a medium, nonreactive saucepan, combine the remaining 4 cups of blackberries, sugar, water, lemon zest, and nutmeg. Over medium heat, warm the berries until they begin to steam. Using a fork or the back of a spoon, smash some of the berries. Once the sugar has dissolved remove from the heat. Taste and add lemon juice and more sugar, if necessary. If not using immediately, cover and refrigerate.
When ready to serve, reheat the blueberry sauce until warm and stir in the reserved blackberries.
In a mixing bowl, combine the heavy cream, sugar, and vanilla. Whip until medium peaks form and the beaters leave tracks on top of the cream.
Put the bottom half of each biscuit on a plate. Spoon on about a ½ cup of the blackberry mixture, additional fresh berries, and a dollop of cream. Cover with the biscuit top. Serve immediately, passing any remaining blackberry mixture at the table.