Preheat your oven to 350°F (177°C) and line a 9x13-inch baking pan with parchment paper.

In a large bowl, whisk together flour, granulated sugar, brown sugar, baking powder, and salt.

Cut in the chilled butter until the mixture resembles coarse crumbs. Reserve 1 ½ cups for streusel topping.

Press the remaining mixture into the bottom of the pan to form the crust.

Par-bake the crust for 15 minutes or until edges are lightly golden. Allow to cool slightly.

In a bowl, combine strawberries, sugar, lemon juice, cornstarch, strawberry jam, and vanilla extract. Mix well.

Spread the strawberry filling over the crust evenly.

Crumble the reserved mixture over the filling and gently press down.

Bake for 40-45 minutes until topping is golden brown and filling is bubbling.

Cool the bars at room temperature for 2-3 hours before slicing, or chill for cleaner cuts.

For optional glaze, whisk together confectioners’ sugar and milk/heavy cream and drizzle over bars before serving.