Blackberry-nectarine Cobbler

Blackberry-nectarine cobbler, adapted from gourmet.com

1 1/4 cups plus 1/2 teaspoon sugar
1 tablespoon cornstarch
2 nectarines, pitted and cut into 1/2-inch-thick wedges
3 pints blackberries
2 cups all-purpose flour
2 teaspoons baking powder
3/4 teaspoon salt
1/2-cup (or so) vegetable oil
3/4 cup soy milk

Preheat oven to 425°F. Whisk together 1 1/4 cups sugar and cornstarch in a large bowl, then add nectarines and blackberries and toss to combine well. Transfer to buttered baking dish and bake in middle of oven until hot, 10 to 15 minutes.

While fruit bakes, whisk together flour, baking powder, and salt in another large bowl, then blend in oil with your fingertips or a fork until mixture resembles coarse meal. Add milk and stir just until a dough forms.
Drop dough onto hot fruit mixture in 6 mounds, then sprinkle dough with remaining 1/2 teaspoon sugar. Bake cobbler in middle of oven until top is golden, 25 to 35 minutes.