Sprinkle the blackberries with 3 tablespoons of the sugar, leave to sit
overnight in the refrigerator, to allow the juices to collect. Drain and
save the juices from the blackberries.
In a food processor, combine the flour, baking powder and 1/8 teaspoon
salt. Pulse to mix thoroughly. Add the butter and 3 ounces of the
chilled cream cheese, then pulse 5 or 6 times until the mixture looks
like coarse crumbs. Drizzle the vinegar and 1½ tablespoons of ice water
over the dough, and pulse 3 times to bring the mixture together into
rough clumps. Turn out onto your work surface, divide into 6 parts and
roll each into a ball. Place the balls on a plate, cover with plastic
wrap and refrigerate for about 45 minutes.
In a small bowl, whisk together the remaining cream cheese, goat cheese, milk and remaining sugar.
Roll out each ball of dough into a 6-inch round on a lightly floured
work surface. Spoon a generous tablespoon of the cheese filling onto the
center of each round, leaving a 1 ½-inch border all around. Spoon a
generous 2 tablespoons of the drained berry mixture on top of the
cheese. Carefully fold the dough edges up over the filling towards the
center, gently pleating the dough as necessary. If time allows, place
the tarts in the freezer for 20 minutes.
Heat the oven to 400. Bake the tarts until richly golden and crispy, about 25 to 30 minutes.
While the tarts are baking, in a small saucepan, bring the reserved
blackberry liquid to a gentle simmer. Add the olive oil. Let liquid
simmer until reduced by half, approximately 2 to 3 minutes. Let cool
Remove tarts from the oven, drizzle with the reduced blackberry syrup
and fresh thyme leaves. Let cool until cheese filling sets. Serve to