Blueberry Pie Bars

Preheat the oven to 375°F. Butter 9 x 9 baking dish. Line the pan with a piece of parchment paper, cut so that it extends on two sides to easily remove it from the pan.

In a medium bowl, mix the flour, brown sugar, oats, and salt. Cut in the butter with a pastry cutter or fork. As it incorporates, use fingers to knead until it becomes an even, consistent dough with no more dry bits of flour (this takes a while, so be patient!). Use your fingers to crumble it into small crumbles and measure out 1 ¾ cup for the topping.

Pour the remaining crumbles into the prepared pan, and press it into an even layer for the crust of the bars. Use the bottom of a measuring cup to press in the dough and make it flat and even.

In a medium bowl, mix the blueberries, granulated sugar, cornstarch, lemon juice, and vanilla extract. Spread them in an even layer over the crust.

Add the reserved crumbles over the top in an even layer.

Bake for 1 hour, until the edges are golden brown. Remove from the oven and cool on cooling rack for 30 minutes. Then transfer to the refrigerator and for 1 hour. Remove from the fridge and use the parchment to remove the bars from the pan. Cut into 16 even squares. Store bars up to 1 week refrigerated (with parchment paper between the layers if stacked), or 3 months frozen.