Rhubarb Shortbread Bars
For the shortbread crust and crumble:
2 1/2 cups all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon salt
1 cup unsalted butter, cold and cubed
3/4 cup granulated sugar
1 large egg
1 teaspoon vanilla extract
For the rhubarb filling:
3 cups fresh rhubarb, finely chopped
3/4 cup granulated sugar
1 tablespoon cornstarch
1 tablespoon lemon juice
1/2 teaspoon vanilla extract
Preheat your oven to 350°F. Line a 9x13-inch baking dish with parchment paper, leaving an overhang on the sides.
In a large bowl, combine flour, baking powder, and salt.
In another bowl, cream the butter and sugar until light and fluffy. Add the egg and vanilla extract and mix until combined.
Gradually add in the dry ingredients and mix until the dough is crumbly but holds together when pressed.
Press two-thirds of the dough into the bottom of the prepared pan to form an even crust. Set the remaining dough aside for the topping.
In a medium saucepan, combine the rhubarb, sugar, cornstarch, lemon juice, and vanilla. Cook over medium heat, stirring occasionally, until the rhubarb breaks down and the mixture thickens, about 8–10 minutes. Let cool slightly.
Spread the rhubarb filling evenly over the crust in the pan.
Crumble the remaining dough over the top of the rhubarb layer.
Bake for 35–40 minutes or until the top is golden and the filling is bubbling slightly.
Cool completely in the pan, then chill in the refrigerator for at least 1 hour before slicing.
Cut into bars and serve chilled or at room temperature.