Preparation

• Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper.
• In a large bowl, whisk together 2 cups flour, ½ cup sugar, and salt. Cut in cold cubed butter with a pastry cutter until the mixture resembles coarse crumbs.
• Add egg and vanilla, mixing until dough begins to come together. Reserve 1 ½ cups of the dough for the topping, then press the remaining crust evenly into the prepared pan.
• In another bowl, combine blueberries, sugar, cornstarch, lemon juice, lemon zest, and optional cinnamon. Toss gently to coat.
• Spread the blueberry mixture over the crust layer. Crumble the reserved dough evenly over the berries.
• Bake for 40–45 minutes, or until the top is golden and the blueberry filling is bubbling.
• Allow bars to cool completely before dusting with powdered sugar, slicing, and serving.