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Rhubarb Shortbread Bars

Rhubarb shortbread bars with a buttery Scottish shortbread base and a thick, spoonable rhubarb jam layer. Baked until the crust is lightly golden, then cooled until set for clean, jammy bar slices.
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Prep Time 20 minutes
Cook Time 55 minutes
cooling 2 hours
Total Time 3 hours 15 minutes
Servings: 16 servings
Course: Dessert
Cuisine: Scottish-American
Calories: 320
Ingredients Equipment Method Notes

Ingredients
  

For shortbread
  • 2 cup all-purpose flour
  • 0.5 cup powdered sugar
  • 1 lb butter, cold and cubed
  • 0.25 tsp salt
For rhubarb layer
  • 4 cup fresh rhubarb, diced
  • 1.5 cup sugar
  • 0.25 cup water
  • 3 tbsp cornstarch
  • 1 powdered sugar for dusting

Equipment

  • 1 sheet pan

Method
 

Prep and bake the shortbread base
  1. Preheat the oven to 350°F and line a 9x13-inch pan with parchment paper. This prevents sticking so the bars release cleanly.
  2. Mix all-purpose flour, powdered sugar, and salt, then cut in cold butter until the mixture looks crumbly. Press the crumbs evenly into the prepared pan to form a flat base.
  3. Bake the shortbread for 25 minutes, until lightly golden at the edges and set in the center. Look for a firm crust with pale golden color.
Cook the rhubarb jam layer
  1. Simmer diced fresh rhubarb with sugar and water until very soft and thick, about 15 minutes. The mixture should lose most of its sharp rhubarb bite and look glossy.
  2. Mix cornstarch with a little water, then stir it into the rhubarb mixture and cook until very thick. Remove from heat when it holds shape like jam.
  3. Spread the thick rhubarb mixture over the hot shortbread crust. Use an even layer so the bars slice with consistent thickness.
  4. Return the pan to the oven and bake for 15 to 20 minutes more. Bake until the top looks slightly set and the rhubarb layer appears glossy but firm.
Cool, chill, and cut
  1. Cool completely, then refrigerate for 2 hours so the bars fully set. The surface should feel firm when pressed lightly.
  2. Dust with powdered sugar and cut into bars. For clean edges, cut after chilling and wipe the knife between slices.

Notes

For the cleanest bar slices, let the pan cool fully before refrigerating, then cut with a sharp knife. Store covered in the refrigerator for up to 5 days; freeze for up to 2 months if tightly wrapped (thaw in the fridge). For a gluten-free option, substitute a 1:1 gluten-free all-purpose flour blend and ensure it measures by weight for best texture.