Rhubarb Custard Bars
There’s something truly special about rhubarb custard bars. They’re the kind of dessert that hits you with a wave of nostalgia, a jolt of springtime joy, and a creamy, tangy flavor that dances on your tastebuds. In this post, you’ll find the ultimate recipe for Rhubarb Custard Bars—one I’ve tested, tweaked, and perfected over the years. I’ll walk you through every delicious step, from crust to custard to cutting, and share tips, variations, and even those little baking missteps I’ve made so you can avoid them. If you’re ready to bake a pan of creamy rhubarb goodness that screams ‘homemade love,’ let’s get into it.
Why Rhubarb Custard Bars Deserve a Place in Your Recipe Repertoire
Rhubarb custard bars are one of those old-school recipes that never seem to go out of style—and for good reason. The tartness of the rhubarb meets the rich, silky custard in a way that just works. And when that dynamic duo is layered over a buttery shortbread crust? Magic. It’s the kind of dessert that wins over anyone, even those who swear they’re “not rhubarb people.”
I grew up with rhubarb growing in the backyard, and one of the first things I learned to bake on my own—around age twelve—was a simple rhubarb custard pie. Over the years, I’ve taken that idea and turned it into these foolproof bars, perfect for sharing at cookouts, holidays, or, honestly, eating straight from the pan on a Tuesday afternoon.
This recipe’s not just good. It’s memorable. It’s the best rhubarb custard bars recipe because it balances the textures and flavors perfectly—and I’ve made sure it works every time.
Rhubarb Custard Bars: The Perfected Recipe
Ingredients (with exact weights for precision)
Shortbread Crust:
2 cups (250g) all-purpose flour
1/3 cup (67g) granulated sugar
1 cup (226g) unsalted butter, cold and cubed
Custard Filling:
1½ cups (300g) granulated sugar
½ cup (60g) all-purpose flour
1 cup (240ml) half-and-half or whole milk
3 large eggs
1 teaspoon pure vanilla extract
5 cups (500g) diced rhubarb (fresh preferred, frozen okay with adjustments)
Optional Cream Cheese Topping:
6 oz (170g) cream cheese, softened
1½ cups (180g) powdered sugar
1 teaspoon vanilla extract
1 cup (240ml) whipped topping or heavy cream, whipped
Step-by-Step Instructions
Preheat Oven to 350°F (175°C).
Make the Crust:
Combine flour and sugar in a bowl.
Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
Press into the bottom of a greased 9×13-inch baking pan.
Bake for 10–12 minutes until lightly golden.
Mix the Custard Filling:
In another bowl, whisk together sugar, flour, milk, eggs, and vanilla until smooth.
Fold in the rhubarb.
Pour this mixture evenly over the hot crust.
Bake the Bars:
Return pan to the oven and bake for 40–50 minutes, until custard is set and just barely jiggles in the center.
Let cool completely in the pan.
(Optional) Add the Cream Cheese Topping:
Beat cream cheese, powdered sugar, and vanilla until smooth.
Fold in whipped topping.
Spread evenly over the cooled bars and chill for at least 1 hour before slicing.
Ingredient Deep Dive: Getting It Just Right
Rhubarb: Tart, Tasty, and Tricky
When using fresh rhubarb, go for stalks that are firm and deep red—they’ll give you the best flavor and color. Frozen rhubarb works, but be sure to thaw and drain it thoroughly or it’ll water down the custard. Rhubarb’s unique flavor—bright, tangy, slightly sour—is what makes these bars sing.
Crust: Buttery, Firm, Never Soggy
We’re using a shortbread-style crust here. The key is cold butter and a quick pre-bake. Don’t skip the pre-bake—it creates a barrier so your custard doesn’t seep in and make things mushy.
Custard: Creamy Without Being Eggy
I’ve made enough versions of this to know custard can be tricky. Too much egg and it’s rubbery; too little and it won’t set. This ratio is just right. Half-and-half brings richness, and whisking thoroughly is key to a silky texture.
Quality Counts
Use good-quality butter and real vanilla. It’s a simple recipe, so the ingredients really shine through.
Kitchen Tools You’ll Need
9×13-inch baking dish
Mixing bowls
Measuring cups and spoons
Whisk
Spatula
Pastry cutter or fork
Knife and cutting board
Optional: stand or hand mixer for the topping
Tips for Success (Bookmark These)
Let the crust cool slightly before adding filling.
Use a baking sheet under your pan to catch any bubbling-over mess.
Let bars cool completely before cutting for clean slices.
Don’t overbake—custard should still have a little wobble.
If using frozen rhubarb, squeeze out excess water with a paper towel.
Variations & Customizations
Add Texture: Mix in ½ cup of chopped walnuts or oats to the crust for a twist.
Brighten It Up: Add lemon zest to the custard for citrusy contrast.
Make It Spicy: A pinch of ground ginger or cardamom gives a subtle warmth.
Toppings: Drizzle with a powdered sugar glaze, or dust with powdered sugar after chilling.
Gluten-Free? Use a trusted 1:1 gluten-free flour blend and line the pan with parchment for easier lifting.
Common Questions Answered (Troubleshooting)
Why is my custard runny?
It likely wasn’t baked long enough. The center should jiggle slightly but not slosh.
Why is my crust soggy?
You may have skipped pre-baking the crust or didn’t drain your rhubarb well enough.
My rhubarb tastes too tart. What should I do?
Add a touch more sugar to the filling, or balance it with sweet toppings like whipped cream.
Can I make these ahead of time?
Absolutely. They hold up well in the fridge for several days.
Can I freeze rhubarb custard bars?
They’re best fresh, but yes—wrap tightly and freeze for up to a month. Thaw overnight in the fridge.
Storing & Serving Your Rhubarb Custard Bars
Store in an airtight container in the fridge. They’ll keep for up to five days. For serving, I love them chilled straight from the fridge, but they’re also fantastic slightly warmed with a scoop of vanilla ice cream or paired with a cup of afternoon tea.
Why This Recipe Works
This isn’t a random internet recipe—it’s one I’ve made dozens of times, for everything from family brunches to potlucks. The crust holds firm, the custard sets like a dream, and the rhubarb is the star it was meant to be. By balancing richness, tartness, and texture, these bars deliver every time.
Pair It With These Recipes
If you love these Rhubarb Custard Bars, you’ll also enjoy these other reader favorites:
A Final Note From My Kitchen
I’ve made this recipe in tiny kitchens, at midnight, with kids hanging on my legs, and for quiet Sunday afternoons when baking felt like therapy. Every time, these rhubarb custard bars brought smiles. They’re easy, dependable, and unforgettable.
And now they’re yours.
Rhubarb Custard Bars
Ingredients
Shortbread Crust:
- 2 cups 250g all-purpose flour
- 1/3 cup 67g granulated sugar
- 1 cup 226g unsalted butter, cold and cubed
Custard Filling:
- 1½ cups 300g granulated sugar
- ½ cup 60g all-purpose flour
- 1 cup 240ml half-and-half or whole milk
- 3 large eggs
- 1 teaspoon pure vanilla extract
- 5 cups 500g diced rhubarb
Optional Cream Cheese Topping:
- 6 oz 170g cream cheese, softened
- 1½ cups 180g powdered sugar
- 1 teaspoon vanilla extract
- 1 cup 240ml whipped topping or heavy cream, whipped
Instructions
- Preheat oven to 350°F (175°C).
- In a large bowl, mix 2 cups flour and 1/3 cup sugar.
- Cut in cold butter until the mixture resembles coarse crumbs.
- Press into a greased 9x13-inch baking dish.
- Bake for 10–12 minutes until lightly golden.
- Meanwhile, whisk sugar, flour, milk, eggs, and vanilla until smooth.
- Fold in diced rhubarb.
- Pour mixture over the warm crust.
- Bake an additional 40–50 minutes, until custard is set but slightly jiggly in center.
- Cool completely in the pan on a wire rack.
- (Optional) For topping: Beat cream cheese, powdered sugar, and vanilla until smooth. Fold in whipped topping. Spread over cooled bars.
- Chill at least 1 hour before cutting into squares.
Notes
- Use fresh rhubarb for best flavor and texture; if using frozen, thaw and drain completely.
- Let bars cool fully before slicing for clean edges.
- Add lemon zest or cardamom to the filling for a flavor boost.
- Store in refrigerator for up to 5 days.
Happy baking—and if you try them, let me know how they turned out. Did you go with the cream cheese topping? Did you eat three before anyone else got a bite? No judgment here. That’s exactly how it should be.
