Mixed Berry Streusel Bars

Streusel: Preheat oven to 350°F. Lightly grease an 8” x 8” square pan with cooking spray. Line with parchment paper to create a sling, with an overhang on all four sides.
In a large mixing bowl, combine the flour, sugar, baking powder, and salt. Add the melted butter and vanilla and mix together with a fork until the mixture is fully combined and crumbly.
Add a little more than half of the streusel to the bottom of the prepared pan and press down until firmly and evenly packed down. Bake for 13-15 minutes or until golden brown on the edges. Allow to cool for at least 10 minutes.
Berries: In another bowl, combine the berries, sugar, lemon juice, and cornstarch. Toss with a spoon until combined. Once the streusel base has cooled, add the berries and spread into an even layer.
Break up the remaining streusel into small clumps and sprinkle over the berries to create an even layer. Bake for 24-26 minutes, or until the streusel starts to get golden brown. Allow to cool completely then cut into 8 equal pieces.
Glaze: In a small mixing bowl, whisk together the powdered sugar, lemon juice, and lemon extract until combined. Drizzle the glaze over the bars.
Serve chilled or at room temperature and enjoy!