6-8cupspeeled and sliced fresh peaches (about 7-8 medium peaches)(or about 2 lbs. frozen, sliced peaches)
2cupsfresh blueberries(or substitute with frozen blueberries)
⅓cupgranulated sugar
Grated zest and juice of 1 lemon
2 ½tablespoonscornstarch
For the Topping
1cupall-purpose flour
½cupgranulated sugar
1teaspoonbaking powder
½teaspoonsalt
6tablespoons(¾ stick) cold salted butter,cubed
⅓cupcold buttermilk, or more if needed
Coarse sugar
Optional, for serving: vanilla ice cream
Instructions
Preheat the oven to 425°F.
Prepare the Filling
In a large bowl, combine peaches, blueberries, sugar, lemon zest, lemon juice and cornstarch. Let the mixture sit for 10-20 minutes.
Transfer the peach mixture to a 12-inch cast iron skillet or a 9 x 13-inch baking dish.
Prepare the Topping
In a medium bowl, whisk together the flour, granulated sugar, baking powder and salt. Using a pastry blender, fork, or your fingers, work in the butter until it’s in pea-sized pieces. Add the buttermilk, stirring gently just until dough forms. If the mixture seems too dry, stir in a little bit more buttermilk.
Drop 8 biscuit-sized dollops of the mixture on top of the peaches. Sprinkle with coarse sugar.
Bake until the top is golden brown and the filling is bubbly, about 25-30 minutes for fresh fruit (or 30-35 minutes for frozen fruit). If the top starts to get too dark before the filling is done or the biscuits are cooked through, tent loosely with foil. Let rest for 5-10 minutes. Serve with ice cream, if desired.
Notes
Fresh or frozen peaches and blueberries both work well.
Do not thaw frozen fruit before using.
Increase cornstarch to 3 tablespoons when using frozen fruit.
Peach skins can be left on or peeled.
Cold butter creates the flakiest biscuit topping.
Don't overmix the dough.
Sprinkle coarse sugar on top for extra crunch.
Tent loosely with foil if the topping browns too quickly.
Store leftovers in the refrigerator for up to 4 days.