Rhubarb and Custard Crumble Bars (Print Version)

Fruity custard bars with tangy rhubarb, creamy vanilla filling, and golden buttery crumble topping for tea time.

# What You Need:

→ Rhubarb Layer

01 - 14 oz fresh rhubarb, trimmed and chopped
02 - 5.3 oz granulated sugar
03 - 1 tablespoon fresh lemon juice
04 - 1 tablespoon cornstarch

→ Shortbread Base & Crumble

05 - 2 cups all-purpose flour
06 - 1 cup rolled oats
07 - 10.6 oz unsalted butter, cold and cubed
08 - 3.5 oz light brown sugar
09 - 1/2 teaspoon salt

→ Custard Layer

10 - 1.3 cups whole milk
11 - 2 large egg yolks
12 - 2.1 oz granulated sugar
13 - 2 tablespoons cornstarch
14 - 1 teaspoon vanilla extract

# Directions:

01 - Preheat oven to 350°F. Line a 9-inch square baking pan with parchment paper, allowing excess paper to hang over edges for easy removal.
02 - Combine rhubarb, sugar, lemon juice, and cornstarch in a saucepan. Cook over medium heat, stirring frequently, until rhubarb softens and mixture thickens, approximately 8-10 minutes. Transfer to a bowl and allow to cool.
03 - In a large bowl, combine flour, oats, brown sugar, and salt. Rub in cold butter using your fingertips or a pastry cutter until mixture resembles coarse breadcrumbs.
04 - Press two-thirds of the crumble mixture firmly onto the bottom of the prepared pan, creating an even, compact base. Reserve remaining crumble for topping.
05 - Bake base for 15 minutes until lightly golden. Remove from oven and allow to cool slightly.
06 - Heat milk in a saucepan until steaming but not boiling. In a separate bowl, whisk together egg yolks, sugar, and cornstarch until smooth. Slowly pour hot milk into egg mixture while whisking continuously. Return mixture to saucepan and cook over medium heat, stirring constantly, until thickened, approximately 2-3 minutes. Remove from heat and stir in vanilla extract.
07 - Spread cooled rhubarb filling evenly over the baked base. Pour prepared custard layer evenly over the rhubarb.
08 - Sprinkle reserved crumble mixture evenly across the custard layer.
09 - Bake for 30 minutes, or until crumble is golden and custard is just set. Do not overbake.
10 - Allow bars to cool completely in the pan. Refrigerate for at least 2 hours before removing from pan and cutting into 16 bars.

# Expert Advice:

01 -
  • The tartness of rhubarb cuts through the sweet custard in a way that feels both comforting and bright.
  • You get three textures in one bite: crumbly base, silky custard, and crunchy topping.
  • They slice cleanly after chilling and hold up beautifully on a serving platter.
  • It uses up a lot of rhubarb without feeling heavy or overly sweet.
02 -
  • Don't skip chilling the bars, or they'll fall apart when you try to cut them.
  • The custard will look a little loose when it comes out of the oven, but it sets perfectly as it cools.
  • If your rhubarb is very thick, chop it into smaller pieces so it cooks down evenly.
  • Press the base firmly, or it will crumble apart when you layer the filling on top.
03 -
  • Use a sharp knife dipped in hot water and wiped dry between cuts for the neatest slices.
  • If you don't have a pastry cutter, use two forks or just rub the butter in with your fingers, it's faster and works just as well.
  • Make the custard ahead and keep it covered in the fridge for up to a day before assembling.
  • Line your pan well, the parchment overhang is your best friend when it's time to lift the bars out.
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