2 T. cornstarch
1 1/2 c. plus 1 t. sugar, divided
5 c. blackberries
2 lb. peaches, peeled, pitted, and cut into 1/2-inch thick wedges
3 c. flour
1 T. baking powder
1 t. salt
1 c. cold unsalted butter
1 c. plus 3 T. milk
Preheat oven to 425 degrees and grease a 9x13-inch pan.
Whisk cornstarch and 1 1/2 cups sugar together in bowl. Add blackberries and peaches, then toss to combine well. Pour into greased pan and bake until just bubbling, 10-15 minutes.
While fruit is baking, whisk flour,baking powder, and salt in another bowl. Cut in butter until mixture resembles coarse meal. Add milk and stir just until dough forms.
Remove fruit from oven and drop dough in 12 mounds, about 1/3 cup each, on top of hot fruit. Sprinkle with remaining sugar. Bake until top is golden, 25-35 minutes. Serve warm.
Notes: Other than skipping the sprinkling of sugar, we made this as directed and it was delicious. Although it would be great with ice cream, we enjoyed it plain. Next time I may add a little cinnamon to the flour mixture when I'm making the dough, just for kicks.