Rhubarb Crumble Bars are a must bake summer dessert recipe. They feature a thick and generous base, a juicy, sweet and tart rhubarb compote, and a crispy oat crumble on top.
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An original crumble bars recipe
I had high expectations about this dessert as it reminded me of something I used to eat when I lived in Sweden, although I couldn’t quite remember what it was exactly or name it. It was like a pie, but like a crumble on top, like bars, but on the pie side… In short, I was looking for an awesome rhubarb dessert, stuck in my memories, and I was determined to make it happen.
I created crumble bars. Berry crumb bars are very popular, and there are indeed countless of raspberry crumble bars recipes (the healthy ones that look almost too fragile, the ones made with the exact same crust for the top and bottom parts, and the other ones with an insane amount of sugar). Well today, I’m sharing rhubarb crumb bars instead, and I bet you will soon be obsessed with them!
A juicy, tart and sweet rhubarb dessert
While searching for the perfect rhubarb crumb bars recipe, I took some time to check the recipes in Swedish (yep, I can still read Swedish!). Interesting fact: I noticed that Swedish recipes contain most of the time half the amount of sugar American recipes contain.
When it comes to fruit desserts, it’s important to find the right amount of sugar to subtly enhance the flavors but in no way overtake the actual taste of fruits. With rhubarb, this is even more true! Slightly tart by nature, rhubarb calls for a little sugar to enhance its natural flavor, but not too much. This way, you get the perfect balance between tart and sweet.
Ingredients to make rhubarb crumble bars
- Rhubarb. You will need about 4 to 5 long stalks of rhubarb, or approx. 1.3 lb (550g).
- Lemon (zest + juice). It adds a bright flavor as well as a boost of natural pectin to help thicken the rhubarb compote.
- Sugar. It makes the compote a little sweeter and adds a subtly crunchy bite to both the bottom and top crust.
- Cornstarch. It is used to thicken the rhubarb compote.
- All-purpose flour. For both the bottom pie crust and the crumble topping.
- Baking powder. It makes the bottom crust a little thicker and softer, close to a blondie texture.
- Butter. While butter for the bottom part is used softened, the one for the crumble topping is used melted, bringing an irresistible crispy texture.
- Oats. Prefer old-fashioned rolled oats rather than quick oats, they hold their shape much better and do not become mushy.
How to make the rhubarb filling?
Making the rhubarb compote is easy. Stir all the compote ingredients except the cornstarch in a saucepan, and cook on medium heat until bubbling. Lower the heat and add cornstarch, stirring well. Let simmer for 5 more minutes, until the mixture thickens. Let cool for a few minutes before using.
What crust to use for these crumble bars?
Many recipes using the exact same crust at the bottom and top part of the bars. This would have been an easier version for you, I confess. But let’s get out of our comfort zone for a minute and make 2 crusts. The idea? Create a contrast between a rich, buttery bottom, and a crispy top. Both preparations are really easy to make, and you can totally re-use the same mixing bowl for each of them.
The bottom part. To create a rich, buttery and soft bottom crust, I used softened butter (instead of melted butter) and a little bit of baking powder.
The top part. To make it crumbly and perfectly crispy, I used oats and melted butter, with a little bit of sugar.
Baking tips and recipe variations
Bake in a square pan if you want to slice into squares like I did, or use a regular pie dish if you want to slice it in a more classic way. Both versions work equally well.
Note that you can follow the recipe to a T, or you can do half rhubarb and half strawberries. Rhubarb and strawberries go hand in hand together, like for instance in my Meringue Strawberry Rhubarb Pie. Another classic combo is rhubarb and apples. Or if you are interested in the bars but do not have rhubarb at hand, try with any berries of your choice: blueberries, blackberries, raspberries… Serve as is, or with a side of vanilla ice cream or whipped cream, and enjoy!
How to store crumble bars?
You can store these rhubarb crumble bars sliced into squares in an airtight container or in a ziploc bag for a week in the refrigerator and up to 3 months in the freezer. Thaw in the refrigerator for a few hours before eating. Enjoy!
What to do with rhubarb?
- Rhubarb Strawberry Chia Pudding
- Meringue Strawberry Rhubarb Pie
- Swedish Rhubarb Cardamom Buns
- Rhubarb Strawberry Apple Cobbler
- Geometric Rhubarb Galette
More fruit crumble recipes:
- Quick Pear and Chocolate Crumble
- Chai Spiced Dutch Apple Pie
- Best Apple Crumble
- Oat Crumble Blueberry Pie (GF)
Rhubarb Crumble Bars
- Prep Time: 30 mins
- Cook Time: 20 mins
- Total Time: 50 minutes
- Yield: 9 servings 1x
- Category: Cakes and Pies
Rhubarb Crumble Bars are a must bake summer dessert recipe. They feature a thick and generous base, a juicy, sweet and tart rhubarb compote, and a crispy oat crumble on top.
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Ingredients
For the base:
- ½ cup (100g) sugar
- 2 cups (240g) all-purpose flour
- 1 Tablespoon baking powder
- ⅔ cup (150g) salted butter, softened at room temperature
- 1 large egg
For the rhubarb compote:
- 4–5 long rhubarb stalks (3 ½ cups / 550g) diced rhubarb
- ⅓ cup (65g) sugar
- 1 lemon, zest and juice
- 2 ½ teaspoons cornstarch
For the crumble topping:
- 1 cup (100g) old-fashioned rolled-oats
- ½ cup (100g) sugar
- 1 teaspoon vanilla sugar
- ½ cup (100g) salted butter, melted
Instructions
- Preheat the oven to 400°F (200°C) and grease a 9-inch square pan. Set aside.
For the base:
- Mix all the dry ingredients together. Incorporate softened butter and pinch of salt with your finger tips until no lumps remain. Add the egg, and stir well until the dough comes together.
- Transfer the dough to the pan in a thick layer, covering all parts of the bottom of the pan.
For the rhubarb compote:
- Heat rhubarb with sugar, lemon zest and juice on medium heat until bubbling. Lower the heat and add cornstarch, stirring well. Let simmer for 5 more minutes, until the mixture thickens.
- Let cool for 5 minutes, then pour over the base in the pan.
For the crumble topping:
- Mix all the ingredients together and sprinkle over the rhubarb compote.
- Bake for about 20-25 minutes, until the top is slightly golden. Let cool completely, then share in square, and enjoy!
Did you make this recipe?
Lastly, if you make this Rhubarb Crumble Bars, be sure to leave a comment and give this recipe a rating, letting me know how you liked it. And of course, don’t forget to tag me on Instagram! Thank you and enjoy!
SK
Probably the best cake I ever made – delicious.
Delphine Fortin
Oh thank you! I’m so happy you liked these rhubarb crumble bars!
Patti
I just made this recipe and it is so delicious! Had some while it was still warm.mmmmm!
Lori
I made those squares and they were delicious! However I thought the crust was way too thick in the bottom. Next time I will cut the crust in half and double the rhubarb for even more flavour. Great recipe though!
Lis
I’ve just made this, it’s very yummy. Thanks for sharing. How long does it keep for, can it be frozen?
Delphine Fortin
Thank you so much! You can keep it a few days in the refrigerator or freeze in a freezer bag for up to 3 months. I hope this helps. Del
Stephanie
I tried this last week, and it was a hit! I added a few frozen mixed berries to the compote to brighten the color and it turned out great. A nice treat for a boat day, light, sweet, tart and crispy. Perfect combination!
Del’s Cooking Twist
Wonderful idea! I am looking forward to hear about your next realizations if you choose to try more recipes!
Melissa
I have just made this, I didn’t have enough rhubarb, so I added some mixed berries, also I added about 1/2 a cup of coconut to the crumble topping
Delphine Fortin
That’s a very good idea indeed! Last time I baked it myself, I added some raspberries to the rhubarb and it was just perfect. Also love your twist with the coconut addition in the crumble topping. Thanks for sharing! Del
Caroline
The bars taste fantastic. I mistakenly used 1/2 cup aka 1 whole stick of butter in the topping. Wish I would have read the recipe closer! Will make again.
Graham Turner
Hallo there. I’ve made these twice now and they’re fantastic. A real crowd pleaser. I’m going to try with a gooseberry filling next time.
Delphine Fortin
Awesome! Thank you so much for your feedback, I really appreciate 🙂 Del
ED MEYER
I am considering making but will require freezing them, anyone try that and if so how well did they hold up?
Delphine Fortin
Hi! You can absolutely freeze them. I would recommend you let the cake cool completely and freeze before slicing. When ready, you can thaw the whole thing in the fridge (finishing at room temperature if still frozen) and slice it out. If however you want to freeze the bars individually, let the cake cool completely in the fridge before slicing and store in ziploc bags. I hope this helps! Del
Steph K
A thick pie crust, a juicy, sweet and tart rhubarb compote, and a crispy crumble on top.
Diya
I cannot wait to make this! I’m only able to find frozen rhubarb. Is it okay to use fresh strawberries and frozen rhubarb, or should I also freeze my strawberries? Thanks!
Delphine Fortin
Hi! Yes it’s totally fine to use frozen rhubarb but fresh strawberries. I hope this helps! Del
Mel
I used spelt flour and coconut sugar. Turned out great. Thanks for this wonderful recipe
Erika
I have a bunch of rhubarb in my fridge right now and this looks like a pretty darn delicious way to use it up! Beautiful photos too!
ROBYN
Thanks for the recipe. I will try it soon!
Sandy
Amazing recipe!
Held together very well after cooling it down!
Thank you so much 🙂
Lily
It was easy to make and really delicious! I didn’t have any oats, so used just flour instead. The crumble bars were sweet, but also sour. Thank you for this amazing recipe!
Gill
Great tasting, but the bar itself didnt hold together well, making it tricky to hold and eat. Probably needed more cornstarch in the compote and less butter in the topping. The base was amazing though!
A.J.
Bottom crust is substantial, enough to make a larger dish if you wanted to increase the fruit. Takes more time than a crisp and less time than a pie and goodness of both in a bar!
Delphine Fortin
Thanks, A.J.! I’m so glad you liked the recipe 🙂 Del
marina
Voilà une recette que je vais m’empresser d’essayer (je dois avoir encore de la rhubarbe congelée) ! Les photos sont si appétissantes…
Une autre association qui fonctionne bien, c’est la framboise avec la rhubarbe. Et je vois que tu as mis de la vanille, la cannelle va aussi très bien avec la rhubarbe, ou la cardamome.
Delphine Fortin
J’adore toutes tes idées de petit “twists” à la recette Marina. Autant de versions à tester!
LadyMilonguera
Je ne me ferais pas prier pour en piquer un carré…