Blueberry Cornmeal Shortbread Tart

1. Prepare the Tart Crust

In a medium bowl, whisk together the all-purpose flour, cornmeal, confectioners' sugar, light brown sugar, baking powder, and kosher salt. Then, pour in the melted butter and mix until the mixture feels like damp sand with no dry spots left. Press half of this mixture into the bottom and up the sides of a 9-inch tart pan with a removable bottom.

2. Make the Blueberry Filling

Toss the blueberries with light brown sugar, apple cider vinegar or fresh lemon juice, a dusting of flour, and a small pinch of salt until well coated and glistening. Pour the blueberry mixture into the crust, creating an even layer.

3. Add the Topping and Bake

Sprinkle the remaining cornmeal mixture over the blueberry filling, pressing gently into rustic clumps. Bake in a preheated oven at 350 degrees for 40 to 45 minutes, until the filling is bubbling and the crust is golden brown.

4. Cool and Serve

Allow the tart to cool down after baking. This rest period lets the filling set and flavors to meld. The tart can be served at room temperature or chilled.