Tangy and sweet rhubarb shortbread bars with a buttery crumbly base and vibrant rhubarb filling, perfect for spring or summer treats.

1 cup unsalted butter, softened

1/2 cup granulated sugar

2 cups all-purpose flour

1/4 teaspoon salt

3 cups chopped rhubarb (fresh or frozen, thawed)

3/4 cup granulated sugar

2 tablespoons cornstarch

1 teaspoon vanilla extract

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Preheat the oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper, leaving an overhang for easy removal.
Cream together the softened butter and sugar until light and fluffy.
Gradually add the flour and salt, mixing just until combined and a crumbly dough forms.
Press about two-thirds of the dough evenly into the bottom of the prepared pan to form the crust. Reserve the remaining dough for the topping.
Bake the crust for 15 minutes, or until lightly golden around the edges. Remove and set aside.
In a bowl, combine chopped rhubarb, sugar, cornstarch, and vanilla extract. Stir well until rhubarb is evenly coated.
Spread the rhubarb mixture evenly over the warm shortbread crust.
Crumble the reserved dough over the rhubarb layer to form a crumbly topping.
Return the pan to the oven and bake for 30-35 minutes, until the topping is golden and the rhubarb filling is bubbly.
Allow the bars to cool completely in the pan on a wire rack before lifting out with parchment paper and slicing into squares.

Frozen rhubarb can be used but must be fully thawed and drained.

To keep crust tender, use softened (not melted) butter and avoid overmixing after adding flour.

If filling is watery, add more cornstarch or drain rhubarb well before mixing.

For gluten-free, substitute all-purpose flour with gluten-free baking flour blend.

Store bars in an airtight container at room temperature for up to 3 days or refrigerated up to a week.

Bars freeze well up to 2 months; reheat gently to refresh crust crispness.