• Preheat oven to 375°F. Butter the inside of a 10 inch cast iron pan or a 2 quart baking pan, such as a 9 inch square pan. Place 1 cup of fresh blackberries on a small sheet pan and place into the freezer.

Make the biscuit topping

• Place flour, brown sugar, baking powder, baking soda, and salt into the bowl of a fodd processor. Pulse to comnbine. Add in cubed cold butter and pulse 4 to 5 times, until the butter is about the size of peas.
• Pour cold buttermilk through the opening on top and pulse just until the dough comes together. Dump the dough into a bowl, knead to incorporate any dry bits and place in the refrigerator while you prepare your fruit.

Mix fruit filling

• Peel peaches if desired. I prefer to leave the skins. Remove pit from peaches and slice in ¼ inch slices. Add to a large bowl.
• Sprinkle over top of the fruit with brown sugar, cornstarch, vanilla. cinnamon, nutmeg, ginger, and kosher salt. Add lemon juice and toss to combine. Add frozen blackberries and gently fold in.

Assemble the cobbler

• Place fruit in the bottom of the prepared baking dish. Take handfuls of dough and place all over the top of the blackberry peach filling. Just pinch of pieces of dough and dot to cover most of the fruit.
• Brush the top of the biscuit dough with egg wash, then sprinkle with coarse or granulated sugar, if using.
• Bake for 40-50 minutes, or until the biscuit topping is golden brown and peach filling is bubbling around the edges. To test for doneness, stick a toothpick into the biscuit topping and if it comes out clean, it’s done.
• Remove cobbler from the oven, and set the pan on a wire rack. Cool for 10 minutes before serving. Serve warm with sweetened whipped yogurt for breakfast or vanilla ice cream for dessert.