Rhubarb Custard Bars Shortbread Crust

Featured in: Sweet Treats

Press a buttery shortbread dough into a 9x13 pan and blind-bake until pale golden. Toss chopped rhubarb with sugar and spread over the hot crust, then pour a smooth custard of eggs, sugar, flour, cream and vanilla over the fruit. Bake at 350°F (175°C) for 35–40 minutes until the custard is set. Cool completely, dust with powdered sugar, cut into 16 bars and chill or serve at room temperature.

Updated on Thu, 07 May 2026 03:43:41 GMT
Buttery shortbread crust layered with tangy rhubarb custard, these bars are a delightful springtime dessert. Pin
Buttery shortbread crust layered with tangy rhubarb custard, these bars are a delightful springtime dessert. | potfuljoy.com

On a brisk morning last May, a stray ray of sunshine had me rummaging through the crisper drawer to rescue rhubarb before it wilted. I could hear the garden waking outside, but inside, all I could smell was a memory waiting to happen. Making these rhubarb custard bars feels less like dessert prep and more like a small celebration of spring finally arriving. The tartness of rhubarb mellowed by silky custard is the kind of flavor contrast that makes you pause, if only for a second. Somehow, these bars turn a chilly afternoon into a bright one.

One time, while making these for my neighbor Linda after she broke her foot (and forgot to buy groceries for weeks), my kitchen was so filled with the scent of baking butter and vanilla that my teenager suddenly wandered in to see what was 'smelling so epic.' Afterward, Linda called just to say they transported her straight to a sunny patio, even if she was stuck on the sofa. Even my perpetually skeptical brother-in-law gave them a surprised thumbs-up after his first bite. Baking the bars for someone else turned the process from a simple recipe to a genuine mood-lifter for everyone involved.

Ingredients

  • Unsalted butter: The crusts secret weapon ensures it bakes up both flaky and rich; I always take care to let it truly soften at room temperature for easier creaming.
  • Granulated sugar: Sweetens each layer just right – dont skimp, but do taste your rhubarb to check its tartness first.
  • All-purpose flour: Essential for both the sturdy shortbread base and the silky custard; sifting it keeps things light.
  • Salt: Even a tiny pinch elevates the buttery notes and balances the sweetness.
  • Fresh rhubarb: The centerpiece – always slice it evenly and try to use the crispest stalks for best results.
  • Eggs: Give the custard its lush texture; room temperature makes for super smooth mixing.
  • Heavy cream: Lends that dreamy, decadent mouthfeel to the filling; dont sub with milk unless youre in a true pinch.
  • Pure vanilla extract: Just a teaspoon wakes up all the floral notes in the cream and rhubarb.
  • Powdered sugar (optional): A final dusting for a pretty, bakery-worthy finish and that hint of sweetness on top.

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Instructions

Prep the pan:
Preheat the oven and line your baking pan so the bars will lift out cleanly later, then take a second to appreciate how ready your ingredients look all in a row.
Cream the crust:
Beat butter and sugar until they look pale and pillowy, then mix in flour and salt until you honestly cant resist poking the dough.
Press and parbake:
Spread the dough evenly in your pan using floured fingers or a spatula, and bake just until golden at the edges.
Sugar the rhubarb:
Toss the chopped rhubarb with sugar and let it macerate, releasing that neon-pink juice while you make the custard.
Mix custard filling:
Whisk eggs and sugar together until smooth, then add flour, cream, vanilla, and a pinch of salt, stirring gently – little air bubbles are perfectly fine.
Assemble the layers:
Scatter the sugared rhubarb over the warm crust, then pour the custard right on top and watch the layers settle together.
Bake to set:
Return to the oven; when done, the custard will jiggle only slightly in the center, and the kitchen will smell like sweet, buttery spring.
Cool and finish:
Let the bars cool completely (the hardest part), then dust with powdered sugar before slicing and serving.
Pin
| potfuljoy.com
Pin
| potfuljoy.com

It was during a backyard picnic, with pink-flecked napkins and kids eating straight from the pan, that these bars felt more like a moment than a dessert. Watching everyone go back for seconds (and the grownups sneak thirds) made me realize food sometimes says what words can’t.

Making the Most of Rhubarb Season

Unfamiliar with rhubarb? I used to be, too. Choose stalks that are firm and ruby red – floppy, pale rhubarb can turn stringy when baked. And if you have leftovers, chop and freeze for another round of bars before the season slips away.

Letting the Custard Shine

The balance between tart rhubarb and rich custard is everything here. Dont whisk the custard for too long; just combine until smooth, or it might get too airy and bake up puffy instead of creamy. If the bars pull slightly from the edges, that means they’re baked just right.

Troubleshooting and Baker’s Notes

Ive overbaked these once (okay, maybe twice), but found the custard still tastes dreamy even when a bit too set. If you cut while still warm, custard will ooze, so patience really is your secret ingredient.

  • Use cold, wet knife to slice tidy bars after chilling.
  • Keep leftovers covered in the fridge for up to 3 days.
  • A touch of lemon zest on top brightens the whole pan.
Creamy custard and tart rhubarb slices atop golden shortbread, perfect for spring gatherings and brunches. Pin
Creamy custard and tart rhubarb slices atop golden shortbread, perfect for spring gatherings and brunches. | potfuljoy.com
Creamy custard and tart rhubarb slices atop golden shortbread, perfect for spring gatherings and brunches. Pin
Creamy custard and tart rhubarb slices atop golden shortbread, perfect for spring gatherings and brunches. | potfuljoy.com

However you serve these, may your kitchen fill with sunshine and your plate never be empty for long. Here’s to baking something that always feels like a little surprise for everyone at the table.

Recipe Q&A

How do I know the custard is set?

The edges should be lightly golden and the center will have a slight, gentle wobble when you jiggle the pan; it will finish setting as it cools. If you prefer a firmer set, bake a few minutes longer and test with an instant-read thermometer—about 170°F (77°C) in the center indicates a firm custard.

Can I substitute strawberries for rhubarb?

Yes—substitute up to half the rhubarb with strawberries for a sweeter, less tart filling. Adjust the sugar slightly if using mostly strawberries, since they release more sweetness and juice than rhubarb.

How can I get a crispier shortbread crust?

Use cold, well-chilled butter cut into the flour for a flakier texture, press the dough evenly, and pre-bake until the edges are lightly golden. Adding 1/4–1/2 cup chopped nuts or a touch more sugar can also increase crunch.

Will these bars freeze well?

Yes. Cool completely, cut into bars, and wrap tightly or layer between parchment in an airtight container. Freeze up to 2 months. Thaw overnight in the refrigerator before serving to preserve texture.

How can I prevent a soggy bottom?

Blind-bake the crust until it is set and starting to color at the edges so it forms a seal. Toss rhubarb with sugar and let it macerate briefly, then drain excess liquid before spreading on the hot crust to avoid excess moisture pooling beneath the custard.

Is there a gluten-free option for the crust?

Use a 1:1 gluten-free flour blend designed for baking and chill the dough well before pressing. You may need to adjust liquid slightly; adding a tablespoon of almond flour can improve texture and flavor.

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Rhubarb Custard Bars Shortbread Crust

Buttery shortbread base layered with tangy rhubarb and silky custard for a bright springtime dessert.

Preparation time
25 min
Cooking time
55 min
Total time
80 min

Category Sweet Treats

Difficulty Medium

Origin American

Yield 16 Servings

Dietary specifications Vegetarian

Ingredients

For the Shortbread Crust

01 1 cup (225 g) unsalted butter, softened
02 1/2 cup (100 g) granulated sugar
03 2 cups (250 g) all-purpose flour
04 1/4 tsp salt

For the Rhubarb Layer

01 3 cups (350 g) fresh rhubarb, chopped
02 1/2 cup (100 g) granulated sugar

For the Custard Filling

01 3 large eggs
02 1 cup (200 g) granulated sugar
03 1/2 cup (60 g) all-purpose flour
04 1 1/2 cups (360 ml) heavy cream
05 1 tsp pure vanilla extract
06 Pinch of salt

For Garnish (optional)

01 Powdered sugar for dusting

Instructions

Step 01

Preheat oven: Preheat oven to 350°F (175°C). Grease a 9x13-inch (23x33 cm) baking pan and line with parchment paper.

Step 02

Prepare the shortbread crust: In a bowl, cream butter and sugar together until light and fluffy. Add flour and salt; mix until a soft dough forms.

Step 03

Bake the crust: Press dough evenly into the prepared pan. Bake for 18–20 minutes, or until lightly golden at the edges.

Step 04

Prepare rhubarb layer: While crust bakes, toss chopped rhubarb with sugar and set aside.

Step 05

Prepare custard filling: In a medium bowl, whisk together eggs and sugar until well combined. Add flour, cream, vanilla extract, and salt; whisk until smooth.

Step 06

Assemble bars: Remove the crust from oven. Evenly spread the sugared rhubarb over the hot crust. Pour custard filling over the rhubarb.

Step 07

Bake until set: Return pan to the oven and bake for 35–40 minutes, or until custard is set and lightly golden.

Step 08

Cool and serve: Cool completely in the pan. Dust with powdered sugar if desired. Cut into bars and serve.

Required equipment

  • Mixing bowls
  • Electric mixer or whisk
  • 9x13-inch (23x33 cm) baking pan
  • Parchment paper
  • Spatula

Allergen information

Review each ingredient to identify potential allergens and if uncertain, please consult a healthcare professional.
  • Contains wheat (gluten), dairy, and eggs.
  • Check all packaging if you have food allergies or intolerances.

Nutritional values (per serving)

These values are provided as a general guide only and shouldn't replace professional medical advice.
  • Calories: 225
  • Fat: 11 g
  • Carbs: 29 g
  • Protein: 3 g

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