Gluten Free Blueberry Cobbler
Ingredients
For the pastry topping
1 1/3 cups (187 g) all purpose gluten free flour (I used Better Batter), plus more for sprinkling
1/2 teaspoon xanthan gum (omit if your blend already contains it)
3 tablespoons (27 g) cornstarch (See Recipe Notes)
2 1/2 teaspoons baking powder
1/8 teaspoon baking soda
1/2 teaspoon kosher salt
1/4 cup (50 g) granulated sugar
6 tablespoons (84 g) unsalted butter, chilled and grated on a medium box grater
3/4 cup (6 fluid ounces) buttermilk, chilled
For the blueberries
2 pounds (about 4 cups) fresh or frozen blueberries
1/2 cup (100 g) granulated sugar
1/4 cup (36 g) basic gum-free gluten free flour (See Recipe Notes)
1/8 teaspoon kosher salt
1/2 teaspoon ground cinnamon (optional)
1 teaspoon pure vanilla extract
2 tablespoons (28 g) unsalted butter, melted and cooled
For brushing
1 tablespoon (14 g) unsalted butter, melted with (optional) 1 tablespoon (21 g) pure maple syrup
Notes
For the cornstarch
If you can’t have cornstarch, try arrowroot. If you are using a starchy all purpose flour, like Cup4Cup, in place of the starch, use more of your all purpose flour.
For the gum-free flour in the filling
I prefer this gum-free flour in the filling to cornstarch, since it doesn’t allow the liquid to separate in the filling, even as it cools. In place of the gum-free blend, you can try using just tapioca starch or just superfine sweet (a.k.a. glutinous) white rice flour.
Instructions
Preheat your oven to 375°F. Grease an 9-inch x 12-inch x 2.5-inch baking dish lightly and set it aside. I used an oval dish, but a rectangular dish works fine.
To make the pastry dough, in a large bowl, place the flour, xanthan gum, cornstarch, baking powder, baking soda, salt and sugar, and whisk to combine well.Add the grated butter, and toss to combine, flattening any large clumps of butter. Create a well in the center of the dry ingredients, add the buttermilk and mix until just combined.
Turn the dough out onto a large piece of plastic wrap, press together and wrap tightly. Refrigerate the pastry dough for at least 10 minutes and up to 5 days.
Remove the chilled pastry dough from the refrigerator and turn it out onto a lightly floured surface. Sprinkle it lightly with more flour and roll out into a rectangle that is similar in size and shape to your baking dish.
Place the shaped pastry on a flat surface and then in the freezer to chill while you prepare the filling.
To prepare the filling, in a large bowl, place the blueberries, sugar, flour blend, salt, and (optional) cinnamon, and toss to combine. Add the vanilla extract and melted butter, and toss to combine completely. Transfer the blueberry mixture to the prepared baking dish and spread into an even layer.
Remove the pastry topping from the freezer. To allow steam to escape during baking, cut out a 1/2-inch square or other shape in the very center of the dough. I like to bake the cutout piece, too, just not on top of the cobbler.
Lift the shaped pastry topping and place it on top of the blueberries in the baking dish. Tuck any excess crust that extends over the sides of the baking dish in, and pinch to secure it.
Place the baking dish in the oven and bake for 10 minutes. Remove the dish from the oven, brush the top evenly with the melted butter (and optional maple syrup) mixture, and return to the oven to finish baking (about 25 minutes).
The cobbler is done when the filling is bubbling, the blueberries are fork-tender, and the top is golden brown all over. Remove from the oven and allow to cool for 15 minutes before serving.