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This dessert starts with a soft cake, a layer of rhubarb, then a sweet and crunchy crumble! Rhubarb crumb bars are a light and delicious treat that are easy to make and enjoy.
Rhubarb is often an underrated ingredient that many people tend to forget to use in sweet treats. You may have heard of rhubarb pie, but there are so many other ways to use this unique ingredient! In this recipe, the rhubarb makes a perfectly tart and bright layer that gives these bars a delightful balance of sweet and sour flavors.
The bars have an amazing flavor; they are light enough to be served as a sweet breakfast or lunch, and are sweet enough to eat for dessert. The soft cake paired with the crunchy topping makes for a wonderful combination that everyone will enjoy. There is so much to love about these rhubarb crumb bars!
You can also try Blueberry Pie Cookie Bars and Raspberry Streusel Bars because they both have a fruit layer and a crumb topping. Something about tangy fruits and sweet topping makes for delicious desserts every time.
Table of Contents
Why You’ll Love This Recipe
- These bars feature a gooey rhubarb layer and a crunchy cake layer.
- The combination of sweet and tangy flavors packs a delicious punch.
- Quick and easy to make.
What is Rhubarb?
Rhubarb is a spring vegetable that typically has a green or red color, and although they have no relation, looks similar to celery with its long and thin shape. It is very sour when eaten raw, but has a pleasant tart flavor when cooked. Rhubarb is used for many different dishes both savory and sweet. It is often used in pastries, jams, or desserts because sugar will balance out the flavor nicely!
Recipe Ingredients
For the Cake
- Flour—All-purpose. This will be used in each layer of the dessert.
- Butter—Softened but not melted. For a rich and tender crumb!
- Confectioners Sugar—To keep the cake soft and add a subtle sweetness to the base.
- Eggs—Room temperature.
- Vanilla Extract—To enhance the flavor of the cake base.
- Baking Powder—For a light and airy cake.
- Salt—Helps all of the flavors pop.
- Brown Sugar—Adds a rich sweetness to your rhubarb and crumb topping.
- Rhubarb— Cut into small pieces. For a bright, tart flavor!
See the recipe card for full information on ingredients and quantities.
How to Make Rhubarb Crumb Bars
Step #1. Preheat the oven. Grease a baking dish and set aside. For the cake, beat the butter and sugar together in a small bowl until light and fluffy.
Step #2. Add the egg and vanilla and stir well to combine.
Step #3. Add the flour, baking powder, and salt. Once mixed, add the batter to the greased pan.For the rhubarb layer, add the rhubarb, brown sugar, and flour into a small bowl and toss to combine.
Step #4. Evenly distribute the rhubarb layer over the cake layer. Bake the cake. While the cake is baking, make your crumb topping. In a bowl, melt the butter. Add the flour, brown sugar, and salt. Stir to combine until the mixture is thick. After the cake is partially cooked, remove it from the oven and sprinkle the crumb topping over the rhubarb layer. Continue to bake the cake until it is done. Allow the cake to cool.
Recipe FAQs
No, they are not the exact same thing but they are similar! They are both made from finely ground white sugar, but confectioners sugar also contains a little bit of starch. This usually helps the sugar from clumping when it sits for long periods of time. It also keeps the sugar from melting if used as a topping for a pastry. The two often get confused, and if you are baking treats at home it is not a big deal if you swap them!
Yes, it is important to allow the cake to bake for at least 15 minutes before you add the crumble topping. This is so that the crumble does not sink into the liquidy batter and rhubarb layer. The cake will set enough in 15 minutes to allow the crumble to stay on top and crisp up nicely. If you add it at the same time as the rhubarb layer, it will get lost in the cake rather than become a sweet crust for the bars.
Any leftover crumb bars can be stored at room temperature or in the fridge. Be sure to transfer the bars into an airtight container to keep them fresh. They will stay good for up to 4 days, if they last that long! You can heat them up in the microwave for a few seconds, or enjoy them at room temperature.
Expert Tips
- When measuring your brown sugar, be sure that it is packed into the measuring cup or spoon, to remove any air pockets and get the right measurement!
- Break your thick crumb topping into pieces that are about the size of the end of your pinkie finger, then evenly distribute it over the cake.
- The total baking time for the cake will be about 45-50 minutes.
- Allow the cake to cool for at least an hour before cutting into it and serving so that it can fully set.
More Dessert Recipes To Consider
Pies, Crisps & Tarts
Healthy Pumpkin Pie Recipe
Pies, Crisps & Tarts
Homemade Coconut Cream Pie
Pies, Crisps & Tarts
Homemade Chocolate Cream Pie
Pies, Crisps & Tarts
Hoosier Sugar Cream Pie
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Rhubarb Crumb Bars
Ingredients
For the Cake Layer
- 1/2 cup butter, room temperature
- 1 cup confectioners’ sugar
- 2 large eggs, at room temperature
- 1/2 teaspoon pure vanilla extract
- 3/4 cup flour
- 1/2 teaspoon baking powder
- 1/4 teaspoon salt
For Rhubarb layer
- 1/2 pound rhubarb, cut into 1/2-inch pieces
- 1 tablespoon brown sugar
- 1/4 cup all-purpose flour
For the Crumb Topping
- 6 tablespoon butter, melted
- 1 cup all-purpose flour
- 1/2 cup packed brown sugar
- 1/4 teaspoon salt
Instructions
- Preheat the oven to 350 degrees. Grease a 9×9 inch baking dish and set aside.
- For the cake layer, in a small bowl beat the sugar and butter together until light and fluffy, about 2 minutes. Add the egg and vanilla and stir well to combine. Add the flour, baking powder, and salt and stir until just incorporated, do not over mix. Add this batter to the bottom of your greased pan.
- For the rhubarb layer add the rhubarb, brown sugar, and flour into a small bowl and toss well to combine. Evenly distribute the rhubarb layer over the cake layer. Bake the cake and rhubarb layers for 15 minutes.
- While the cake is baking make your crumb topping. In a microwave safe bowl melt the butter. Add the flour, brown sugar, and salt. Stir to combine until the mixture resembles a thick cookie dough.
- After the cake has cooked for 15 minutes, remove it from the oven and gently break off pieces of the crumb topping into large pieces (about the size of the end of your pinkie finger) and evenly distribute the crumb topping over the rhubarb layer.
- Bake the cake an additional 30 to 35 minutes until a toothpick inserted into the center comes out clean. (Total baking time will be 45 to 50 minutes). Allow the cake to cook for at least an hour before serving warm or at room temperature.
Made these tonight — a perfect rhubarb showcase! Just the right balance of tart rhubarb tang sandwiched between two sweet layers. Melissa, I think you are spying on my kitchen — earlier I thought “oh no, I have all this rhubarb and no strawberries,” and not five minutes later this came across my feed. This happens so often with your blog, and I just love what you do here!
I am such a rhubarb fan! Love the pie, love a good crisp but I have yet to try them in a crumb bar variety. Looks divine!
I am such a rhubarb fan! Love the pie, love a good crisp but I have yet to try them in a crumb bar variety. Looks divine!
These look great! I definitely need to break out of the traditional strawberry-rhubarb combo. Putting these crumb bars on my list before rhubarb is gone for the year!
You conquered your crumb bars!!! And they look amazing!! I love rhubarb all by itself, no strawberries needed.
Rhubarb is VERY popular in our house, and I am certain that these would be gone in minutes!