There’s something magical about the tangy-sweet flavor of rhubarb custard bars that instantly brings back memories of springtime baking in my grandmother’s kitchen. These buttery bars, layered with a soft, creamy custard and a punch of rhubarb, were always a family favorite. Whether you’re working with fresh garden rhubarb or pulling a stash from the freezer, this recipe brings out the best in this seasonal star. In this post, I’ll share not only how to make the perfect rhubarb custard bars, but also tips for storage, variations like adding strawberries, and whether frozen rhubarb works just as well.
Table of Contents
Why We Love Rhubarb Custard Bars
Rhubarb’s Tangy Charm
Rhubarb often flies under the radar, but in these rhubarb custard bars, it’s the absolute star. This tart vegetable masquerading as fruit adds a sharp contrast to the silky, sweet custard layer. When baked into a bar with a buttery crust, it becomes a springtime treat that’s hard to resist. Using rhubarb in desserts can be intimidating for some, but this recipe makes it incredibly approachable—even if it’s your first time working with it.
A Nostalgic Dessert Reimagined
There’s something wonderfully nostalgic about these bars. The recipe itself is inspired by generations of Midwest kitchens where rhubarb plants grow abundantly in backyards. We’ve reimagined that old-fashioned charm with a few tweaks to make it even better—without losing its roots. Whether you’re baking for a picnic or just need something sweet for Sunday dinner, these rhubarb custard bars deliver on flavor and comfort.
Throughout this post, I’ll also guide you on how to incorporate other fruits like strawberries, how to use frozen rhubarb effectively, and how to keep leftovers fresh for days.
Looking for more spring dessert ideas? These bars pair wonderfully with a floral tea or a fresh Strawberry Spinach Salad for a light, seasonal meal.
Ingredient Spotlight: Rhubarb and More
Rhubarb
This hardy perennial vegetable is known for its bright red stalks and sharply tart flavor. While its leaves are toxic, the stalks become deliciously sweet when cooked. Choose stalks that are firm and vibrant, avoiding limp or overly green ones. Fresh rhubarb is ideal, but frozen works in a pinch.
Butter
Using unsalted butter gives you control over the flavor. It forms the base of the shortbread crust, creating that melt-in-your-mouth texture that pairs so beautifully with the creamy custard.
Eggs
Eggs are the backbone of the custard, creating structure and richness. Make sure they’re at room temperature for the smoothest blend.
Milk
Whole milk is best here—rich enough to complement the eggs and give the custard its silky consistency. You can experiment with half-and-half or even a splash of cream for a denser result.
Sugar and Vanilla
Granulated sugar balances the tart rhubarb, while vanilla rounds out the flavor profile. For a twist, consider adding lemon zest or almond extract for a different layer of depth.
Ingredients
For the Crust:
- 1 cup (2 sticks) unsalted butter, softened
- 1/2 cup granulated sugar
- 2 cups all-purpose flour
- 1/4 tsp salt
For the Filling:
- 2 cups chopped fresh rhubarb (about 1/2-inch pieces)
- 4 large eggs
- 1 1/2 cups granulated sugar
- 1/4 cup all-purpose flour
- 1/2 tsp salt
- 1/2 tsp vanilla extract
- 1 1/2 cups whole milk
Instructions
Step 1: Make the Shortbread Crust
- Preheat oven to 350°F (175°C). Grease or line a 9×13-inch pan.
- Cream butter and sugar until light and fluffy.
- Add flour and salt, mixing until a soft dough forms.
- Press evenly into the pan and bake for 15 minutes, until slightly golden.
Step 2: Prepare the Custard
- In a large bowl, whisk eggs, sugar, flour, and salt.
- Add vanilla and milk, mixing until smooth.
- Fold in rhubarb and pour over the pre-baked crust.
Step 3: Bake and Cool
- Return to oven and bake for 40–45 minutes.
- The custard should be set but slightly jiggly.
- Let cool to room temperature, then refrigerate for 2 hours.
Serving Suggestions
These bars are best served chilled. Try dusting them with powdered sugar or topping with a dollop of whipped cream. They also pair beautifully with:
- Iced herbal teas
- Sparkling lemonade
- A glass of chilled rosé or white wine
Tips for the Perfect Bars
- Chill Time Matters: Cooling lets the custard firm up, making clean cuts and better texture.
- Adjust the Sweetness: Rhubarb’s tartness varies. Taste a raw piece and add a little more sugar if needed.
- Parchment Lining: For easy removal, line your pan with parchment and leave an overhang.
These bars are best served chilled. If you’re into fruity desserts with cream cheese elements, you’ll also love the Honey Peach Cream Cheese Cupcakes — another perfect spring treat!
And if you’re baking for a crowd, consider adding Easter Cake Mix Cookie Bars or Carrot Cake Cupcakes to your table for variety.
Make It Your Own
Want to experiment? Here are some variations:
- Strawberry-Rhubarb Bars: Replace half the rhubarb with chopped strawberries.
- Nutty Twist: Add slivered almonds or coconut to the crust for extra texture.
- Citrus Zing: Mix lemon zest into the custard for a fresh, zesty flavor.
FAQs
Can I freeze Rhubarb Custard Bars?
Yes! Cut into squares, layer with parchment, and freeze in an airtight container for up to 2 months.
What’s the best way to store leftovers?
Store in the fridge in an airtight container. Best enjoyed within 4–5 days.
Can I make this gluten-free?
Yes, use a 1:1 gluten-free baking flour for both the crust and custard mixture.
Can I make it dairy-free?
Try using plant-based butter and a creamy non-dairy milk like oat or almond. Results may be slightly less rich but still tasty.
Why is my custard runny?
It likely needed more time in the oven. Bake until the center is just set. Also, ensure your oven is at the correct temperature.
Rhubarb Custard Bars
Equipment
- 9×13 inch baking dish
- Mixing Bowls
- Whisk
Ingredients
For the crust:
- 2 cups all-purpose flour
- 3/4 cup unsalted butter cold and cubed
- 1/4 cup powdered sugar
For the custard filling:
- 3 large eggs
- 1 1/2 cups granulated sugar
- 1/2 cup all-purpose flour
- 1/2 tsp vanilla extract
- 1/4 tsp sea salt
- 4 cups fresh rhubarb chopped
For the topping (optional):
- 1 cup heavy whipping cream
- 2 tbsp powdered sugar
- 1/2 tsp vanilla extract
Instructions
- Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish or line with parchment paper.
- In a medium bowl, combine 2 cups flour and 1/4 cup powdered sugar. Cut in the cold butter using a pastry cutter or hands until the mixture resembles coarse crumbs.
- Press the crust mixture evenly into the bottom of the prepared pan.
- Bake the crust for 12–15 minutes, or until lightly golden.
- Meanwhile, in a large bowl, whisk together eggs, granulated sugar, 1/2 cup flour, vanilla, and salt until smooth.
- Stir in the chopped rhubarb until well coated.
- Pour the rhubarb custard mixture over the pre-baked crust and spread evenly.
- Return the pan to the oven and bake for 40–45 minutes, or until the custard is set and top is lightly golden.
- Cool completely at room temperature, then refrigerate for at least 1 hour before slicing.
- For optional topping: beat cream, powdered sugar, and vanilla until soft peaks form. Serve with chilled bars.
Notes
A Slice of Tradition
These Rhubarb Custard Bars are more than just dessert—they’re a memory, a tradition, and a delicious way to savor summer. From the snap of the crust to the creamy filling and vibrant rhubarb, each bite tells a story of seasons past and the joy of simple, homemade food.
Whether you’re sharing them at a picnic, wrapping them up for a potluck, or sneaking one straight from the fridge, they’re bound to become part of your family’s summer tradition too.
