Gluten-Free Peach Blackberry Cobbler

I picked some Blackberries today.  Just enough to make Peach Blackberry Cobbler with the peaches in my refrigerator.

6 peaches, peeled pitted, and cut into 1-inch chunks
1 tablespoon cornstarch
2 1/2 tablespoons brown sugar
1/2 teaspoon lemon juice
tiny pinch salt
1  cup blackberries
Topping, as follows

Preheat the oven to 350 degrees.  In a bowl, combine the peaches, cornstarch, brown sugar, lemon juice and salt tossing gently.  Carefully fold in the blackberries and transfer the mixture to a 4-cup baking dish.  Set Aside.

Topping:
1 cup of your favorite gluten-free all purpose baking flour
1/2 teaspoon xantham gum (if not already in your flour)
1/4 teaspoon salt
2 Tablespoons brown sugar, packed
1 teaspoon baking powder
1/8 teaspoon dired ginger
1/8 teaspoon cinnamon
1 pince nuteg
3 tablesppon cold unsalted butter, cut into pieces (I like to freeze mine and grate it into the bowl)
1/3 cup plus 1 tablespoon milk
1 1/2 teaspoon sugar

In a mixed fittes with a paddle attachment, mix the flour,  xantham gum, salt, brown sugar, baking powder, ginger, cinnamon and nutmeg.  Add the butter and mix.  Add 1/3 cup milk and mix just until  combined.  Turn out the dough onto a lightly floured surface and knead a few times to smooth it out.  Form into a ball and roll out into the shape and saze of the baking dish, about 1/2-inch thick.  Place dough on top of the prepared fruit.

Brush the top of the dough with the remaining tablespoon of milk and sprinkle with the granulated sugar.  Place the cobbler on a sheet-pan to catch any juices that may boil over.  Bake until the top is golden brown and juices are bubbling, 25-30 minutes.  Let cool slightly before serving.  Serve warm or at room temperature with whipped cream or ice cream.