This old fashioned recipe makes the best Rhubarb Bars! Rhubarb is the star of these bars, surrounded by a sweet custard and baked onto a shortbread crust. They are perfect for the height of rhubarb season!
This year, I tried a new-to-me recipe that I’ve deemed the BEST Rhubarb Bars ever! Because, oh my goodness, are they good.
I’ve seen this recipe in a variety of church cookbooks, so this seems to be “THE” old fashioned recipe for rhubarb bars. They are also known as Rhubarb Dream Bars.
It starts with a shortbread crust, which we’ll top with a mixture of sugar, eggs, flour, cornstarch, and rhubarb. The sugar/egg mixture creates a custard-like filling, which has the perfect amount of sweetness to complement the tart rhubarb.
Note that the cornstarch is not original to this recipe. I added it after making the original recipe first, which was quite runny. The cornstarch thickens the filling perfectly without adding any additional flavor.
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Tips for making the best rhubarb bars
- Do not to remove the bars from the oven too soon. They should not move at all in the middle when you jiggle the pan. If the middle is still runny, return the pan to the oven for 5 more minutes, then check again.
- I don’t recommend making these with frozen rhubarb. Frozen rhubarb will add too much moisture to the recipe, making them runny.
- Leave time for the bars to chill in the refrigerator before slicing. This will also firm up the filling.
- The star of the show is fresh rhubarb. You’ll need 4–6 stalks, depending on the size of each stalk.
- The shortbread crust is buttery and flaky. We’ll use flour and butter to create the flakiness, and powdered sugar to sweeten it.
- The filling is made of sugar, eggs, flour, and cornstarch. It creates a sweet custard that complements that tart rhubarb nicely.
How to make rhubarb bars
Start by cutting a cold stick of butter into small cubes. The small cubes will be easier to incorporate into the flour/sugar mixture than a whole stick.
Next, place the flour and powdered sugar in a large bowl. Add the cubed butter, and use your hands, a fork, or a pastry blender to work the butter into the flour mixture.
The mixture should stick together when you squeeze it in your palm.
Press the dough into an 8×8-inch baking dish, and bake for 15 minutes at 350°F.
While the crust is baking, chop the rhubarb into one-quarter inch pieces.
Whisk together the flour, sugar, and cornstarch, then stir in the rhubarb and beaten eggs. Pour the mixture over the crust.
Bake for 38–45 minutes. The center should not move at all when you jiggle the pan.
If the center still moves, return the pan to the oven for 5 additional minutes, and test again.
Let cool completely, then refrigerate before slicing for the nicest looking slices.
Can I make rhubarb bars ahead of time?
Rhubarb Bars are great for making ahead. They can be made 1–2 days in advance and stored in the refrigerator before serving.
Frequently Asked Questions
Rhubarb is easiest to find in grocery stores and farmer’s markets in May and June. It typically isn’t available later in the summer, as harvesting rhubarb later in the season can reduce the health of the next year’s crop.
Rhubarb Bars can be frozen for up to 3 months. Keep it tightly covered while frozen, and defrost in the refrigerator.
I recommend keeping rhubarb bars in the refrigerator so they last longer. They will last for up to one week in a covered container.
Rhubarb Bars are easily customizable! Here are a few ideas:
- Add the zest of one lemon to the filling OR the crust (before baking)
- Stir in the zest of one orange to the filling OR the crust (before baking)
- Stir in ¼ teaspoon ground cinnamon to the filling before baking
- Dust the tops of the rhubarb bars lightly with powdered sugar after cooling
More rhubarb recipes
Have you tried this recipe? Please leave a ⭐️⭐️⭐️⭐️⭐️ rating and/or comment below!
The Best Rhubarb Bars
For the crust:
- 1 cup flour
- 5 tablespoons powdered sugar
- ½ cup cold butter, diced
For the filling:
- ¼ cup flour
- 1 cup sugar
- 1 tablespoon cornstarch
- ¾ teaspoon salt
- 2 eggs, beaten
- 2 cups chopped rhubarb
- Preheat oven to 350°F. Grease an 8×8 inch baking dish with cooking spray.
- Whisk 1 cup of flour and the powdered sugar in a large bowl.
- Using your fingers, a fork, or a pastry blender, cut the butter into the flour mixture, similar to making a pie crust. The butter should be the size of small peas and the dough should stick together when pressed together.
- Pour the dough into the baking dish and pat down into an even layer. Bake for 15 minutes.
- Meanwhile, whisk together the ¼ cup flour, sugar, cornstarch, and salt. Gently stir in the beaten eggs and the chopped rhubarb. Only stir JUST until combined.
- Pour the mixture into the baked crust, and bake for another 38–45 minutes. The center should not move at all when you jostle the pan.
- Let cool completely before cutting into bars. For best results, refrigerate for several hours before cutting.