A bright and comforting dessert bar featuring a buttery oat or shortbread crust, tart rhubarb, and a creamy custard layer. These bars strike the perfect balance between tangy and sweet, making them a delightful treat any time of day.
Why You’ll Love This Recipe
- Perfect seasonal tart-sweet combo – tangy rhubarb balanced with rich custard
- Easy to prepare – just layer and bake, no fussy techniques
- Great make-ahead dessert – delicious when served warm or chilled
- Customizable texture – use oat crust, gluten-free flour, or almond topping
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
- Fresh rhubarb, chopped
- Granulated sugar (for rhubarb)
- Cornstarch
- Eggs
- Granulated sugar (for custard)
- All-purpose flour
- Butter, chilled
- Ground oats or rolled oats (optional crust variation)
- Vanilla extract
- Salt
Directions
- Prepare crust: Mix chilled butter, flour, oats (if using), sugar, and a pinch of salt until crumbly. Press half into a lined baking pan.
- Par-bake crust: Bake at 350 °F (175 °C) for about 15 minutes, until lightly golden.
- Prep rhubarb layer: Toss chopped rhubarb with sugar and cornstarch. Spread evenly over the warm crust.
- Make custard: Whisk together eggs, sugar, cornstarch, flour, vanilla, and a pinch of salt until smooth. Pour over the rhubarb layer.
- Bake bars: Return to the oven and bake for 30–35 minutes, or until the custard is set and the top is just tinted golden.
- Cool & cut: Let cool completely, then chill for at least 2 hours (or overnight) before cutting into bars.
Servings and timing
- Servings: Makes about 16 bars (2-inch squares)
- Prep time: 20 minutes
- Bake time: ~45–50 minutes (including par-bake and final bake)
- Chill time: 2 hours or overnight
- Total time: ~3 hours (mostly hands-off)
Variations
- Oat crust option: Add rolled oats to the crust for extra nuttiness and whole-grain texture
- Gluten-free: Use a 1-to-1 gluten-free baking flour blend
- Almond topping: Sprinkle sliced almonds on top before baking for crunch
- Lemon zest: Add a teaspoon of fresh lemon zest to custard for brightness
- Berries: Mix in raspberries or strawberries with the rhubarb for flavor contrast
Storage/Reheating
- To store: Cover and keep in the refrigerator for up to 5 days
- To reheat: Serve at room temperature or warm gently in a 300 °F oven for 5–7 minutes
- Freezing: Freeze bars (cut into portions) in airtight containers with parchment layers for up to 2 months. Thaw overnight in the fridge before serving
FAQs
What is the best time of year to get rhubarb?
Fresh rhubarb is in peak season from April through June, though frozen rhubarb is available and works well.
Can I use frozen rhubarb?
Yes—just thaw and drain excess moisture before tossing with sugar and cornstarch.
Do I have to chill the bars before cutting?
Yes—the filling firm up significantly as it chills, making clean slices much easier.
Can I make the crust nut-free?
Absolutely—just omit oats and almonds, and stick with almond-free flour.
Is there a dairy-free option?
Use vegan butter or coconut oil in place of butter and ensure your flour blend is dairy-free.
How tart will these taste?
Expect a tangy-sweet balance; adjust sugar on the rhubarb layer to your taste, adding more if your rhubarb is very tart.
Can I add spices?
Yes—add ¼ tsp ground ginger, cinnamon, or cardamom to the custard for warmth.
Can I bake this in a different size pan?
Yes—bake in an 8×8 inch pan, but note bars will be thicker and may need additional bake time.
What’s a good garnish?
Top with a dusting of powdered sugar, whipped cream, or a dollop of yogurt before serving.
Can I prepare components ahead?
Yes—pre-bake the crust and prep the rhubarb the day before; assemble and bake custard layer when ready.
Conclusion
Rhubarb Custard Bars are a lovely seasonal treat that combine simplicity and flavor in every bite. Tangy rhubarb melds with creamy custard atop a buttery crust—perfect for spring gatherings, afternoon tea, or a make-ahead dessert you’ll reach for again and again. Enjoy the fresh, bright taste of rhubarb in these delicious bars.
Print
Rhubarb Custard Bars
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Total Time: 55 minutes plus chilling time
- Yield: 16 (2×2″) bars 1x
- Category: Dessert/Bars
- Method: Bake
- Cuisine: American
- Diet: Vegetarian
Description
Sweet-tart rhubarb combined with a creamy custard in a buttery shortbread base, baked into delicious bars perfect for spring or summer dessert.
Ingredients
- Crust:
- 1 1/2 cups all-purpose flour
- 1/4 cup granulated sugar
- 1/2 tsp salt
- 10 tbsp unsalted butter, cold and cubed
- Custard Topping:
- 2 cups rhubarb, chopped (fresh or frozen)
- 2/3 cup granulated sugar
- 2 tbsp all-purpose flour
- 2 large eggs
- 1/2 cup milk (whole or 2%)
- 1 tsp vanilla extract
- Optional: powdered sugar for dusting
Instructions
- Preheat oven to 350 °F (175 °C). Line an 8×8″ baking pan with parchment, leaving an overhang.
- Make crust: in a bowl, whisk flour, sugar, and salt. Cut in cold butter until mixture resembles coarse crumbs. Press firmly into prepared pan.
- Bake crust 15 minutes until lightly golden. Remove from oven.
- While crust bakes, toss rhubarb with 2 tbsp sugar and 2 tbsp flour to coat evenly.
- In a separate bowl, whisk eggs, remaining sugar, milk, and vanilla until smooth.
- Evenly distribute rhubarb over hot crust. Pour custard mixture over top.
- Return pan to oven and bake 25–30 minutes, until custard is set but slightly jiggly in center.
- Cool completely in pan, then lift out using parchment. Chill 2+ hours before slicing into bars.
- Dust with powdered sugar before serving, if desired.
Notes
- For a firmer filling, bake up to 35 minutes.
- Leftover bars keep in the fridge for up to 4 days.
- Rhubarb adds natural tartness—if using frozen, thaw and drain excess liquid before mixing.
- You can add a teaspoon of lemon zest to the custard for extra brightness.
- Cut bars while cold for clean edges; let come to room temp briefly before serving.
Nutrition
- Serving Size: 1 bar (2×2″)
- Calories: Approx. 180 kcal
- Sugar: 15 g
- Sodium: 90 mg
- Fat: 8 g
- Saturated Fat: 5 g
- Unsaturated Fat: 3 g
- Trans Fat: 0 g
- Carbohydrates: 24 g
- Fiber: 1 g
- Protein: 3 g
- Cholesterol: 55 mg