In a medium nonreactive bowl, stir together the blackberries, ¼ cup (50 g) of the granulated sugar, the brown sugar, 1 table- spoon of the flour, the vinegar, and the cinnamon. Set aside.
In another medium nonreactive bowl, sift together the remaining ½ cup (65 g) flour, the remaining ½ cup (100 g) granulated sugar, the baking powder, and the salt. Pour in the buttermilk and use a wooden spoon to stir and combine. The batter should be the consistency of pancake batter; it is fine if there are a few lumps. Set it aside.
In a 10-inch (25-cm) cast-iron, skillet, melt the lard over medium heat until it starts to brown around the edge and foam. It should be sizzling; you should hear it. When you hear that lard start to brown and sizzle, pour the batter into the hot skillet. Do not stir it.
Pour the fruit mixture right on top of the batter. Re-move the skillet from the heat.
Transfer the skillet into the pit that you’ve been steadily maintaining at 250°F (120°C). Smoke the cobbler until the crust is golden and crisp-edged, about 1½ hours.
Serve topped with vanilla ice cream if you like.
