For a taste of spring, these moist and chewy rhubarb oatmeal bars are filled with tart rhubarb and sweet strawberry jam. They’re as good as rhubarb pie but so much easier to make!
Looking for more rhubarb recipes? You’ll love this rhubarb layer cake with candied rhubarb curls, homemade rhubarb cordial, and roasted rhubarb ice cream.
Updated: I originally developed this recipe in 2013, but have updated the post in 2021.
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Why You’ll Love This Recipe
Easy to Make. What I love about a crumb bar recipe is how easy they are to make. Since you only need to make one mixture for both the bottom crust and the crumb topping, these bars come together quickly.
So Perfect in the Spring. I look forward to fresh rhubarb from our garden every spring, and these bars are always one of the first recipes I make.
Simple Pantry Ingredients. You’ll just need basic staples to make this recipe, and you probably have everything on hand already.
TIP: Either fresh or frozen rhubarb works equally well in these rhubarb oatmeal bars. You can find fresh rhubarb in grocery stores in early spring (from April-June), or check the freezer section of your local farmer’s market for frozen rhubarb.
Ingredients
Crust and Topping
- All-Purpose Flour. Provides structure and strength to the crust and topping.
- Old-Fashioned Oats. Adds crunch and texture.
- Dark Brown Sugar. Adds sweetness and a hint of molasses.
- Coarse Kosher Salt. Balances the sweetness.
- Baking Powder. Provides a little leavening.
- Cinnamon. Nicely complements the flavor of the rhubarb.
- Unsalted Butter. Adds richness and moisture to bind the crust together.
Filling
- Rhubarb. You can use either fresh, or frozen rhubarb, whichever you can easily find.
- Baking Soda. Neutralizes the bitterness in the rhubarb.
- Granulated Sugar. Adds sweetness and moisture.
- All-Purpose Flour. Helps to thicken the juices of the filling.
- Strawberry Jam. Strawberries are very complementary to rhubarb, and the jam adds more thickness and sweetness.
- Lemon Juice. A touch of lemon helps to balance the sugar and enhances the flavor of the rhubarb and strawberries.
- Vanilla Extract. Flavor.
TIP: If you grow your own rhubarb, you can easily freeze it to bake with later. First, remove and discard the toxic leaves. Wash the stalks well, and let them dry. Chop the stalks into 1/2 inch pieces, and freeze in zip top freezer bags, pressing out as much air as possible.
Instructions
Make the Oatmeal Crust & Topping Mixture.
- Preheat the oven to 350. Spray a square 8×8 baking dish with non-stick spray.
- In your food processor, or with a pastry cutter, combine the crust/topping ingredients until pea-sized pieces of butter remain.
- Reserve 1 ½ cups of the crumbs for the topping (chill in the refrigerator until needed), and press the remainder of the crumbs firmly against the bottom of the baking dish. Bake crust for 20 minutes.
Combine the Rhubarb Filling.
- Meanwhile, in a bowl toss the rhubarb with the baking soda, sugar and flour until all the fruit is coated. Stir in the jam, lemon juice and vanilla.
Bake the Rhubarb Filling.
- After the crust has baked for 20 minutes, remove from the oven.
- Spread the rhubarb mixture over the hot crust. Bake for 30 minutes.
Add the Topping and Finish Baking.
- Sprinkle the reserved crumbs over the fruit and bake for an additional 20-25 minutes until topping is golden brown.
- Let cool on the counter for at least two hours to set before slicing into squares.
Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common baking questions, so that you can be successful in your own baking!
Frequently Asked Questions
What kind of oats do you use in the crust and topping?
I use old-fashioned oats. They have a better texture than instant oats, and cook much more quickly than steel-cut oats, so they’re my go-to oats for cooking and baking.
Should I use fresh or frozen rhubarb?
You can use either, whichever is easiest to find. Depending on where you live, you might only be able to buy fresh rhubarb in early spring (from April-June) in your grocery store. My local grocery store (Kroger) almost never stocks frozen rhubarb, although I’ve been able to find it at Sprouts.
Can I make these bars ahead of time and freeze them?
I haven’t tried freezing these bars, but since the filling is so moist, I’m guessing it would make the crust and topping soggy during the thawing process.
Can I make these bars gluten-free?
Yes, you can easily make gluten free rhubarb oatmeal bars by using your favorite measure-for-measure gluten free flour in place of the all-purpose flour.
What if I want to add fresh strawberries instead of the strawberry jam?
If you do, you’ll need to reduce the strawberries quite a bit first, so they’re not too juicy. I have a recipe for brown butter strawberry crumb bars, which are just fantastic.
How should I store leftover rhubarb bars?
You should refrigerate the bars, in an airtight container, for up to 2 days. The filling is so moist that after 2 days, the crust will start to get a little soft.
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Rhubarb Oatmeal Bars
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet. See FAQs for adjusting to higher or lower elevations.
Ingredients
Crust and Topping
- 1 ½ cups all-purpose flour, spooned and leveled
- 1 cup old-fashioned oats
- ½ cup dark brown sugar, lightly packed
- 1 tsp coarse Kosher salt (if using table salt, use half the amount)
- 1 tsp baking powder
- 1 tsp ground cinnamon
- 1 cup (2 sticks) cold, unsalted butter, diced
Filling
- 12 oz rhubarb, diced into 1/4 – 1/2 inch cubes (about 2 1/2 cups diced)
- ¼ tsp baking soda
- ½ cup granulated sugar
- ¼ cup all-purpose flour, spooned and leveled
- ½ cup strawberry jam or preserves
- 1 tbsp lemon juice
- 1 tsp vanilla extract
Instructions
- Preheat the oven to 350. Spray a square 8×8 baking dish with non-stick spray.
- In your food processor, or with a pastry cutter, combine the crust/topping ingredients until pea-sized pieces of butter remain.
- Reserve 1 ½ cups of the crumbs for the topping (chill in the refrigerator until needed), and press the remainder of the crumbs firmly against the bottom of the baking dish. Bake crust for 20 minutes.
- Meanwhile, in a bowl toss the rhubarb with the baking soda, sugar and flour until all the fruit is coated. Stir in the jam, lemon juice and vanilla.
- Spread the rhubarb mixture over the hot crust. Bake for 30 minutes.
- Sprinkle the reserved crumbs over the fruit and bake for an additional 20-25 minutes until topping is golden brown.
- Let cool on the counter for at least two hours to set before slicing into squares.
I have been watching the rhubarb patch and picked some today and baked these squares. They turned out perfectly and we each had one still slightly warm with some vanilla ice cream for dessert. They are delicious. Great recipe!
Caroline, I’m jealous that you can grow your own! I can’t wait to have a place with my own garden. For now I just have to buy some every time I go to the store and stockpile it in the freezer. I’m so glad you like the recipe! 🙂
These bars are the best ever! I will be making these again and again and again!!
Went out and pick probably the last batch today and whipped these up! Recipe is spot on and thanks for sharing! Delish!
I added 1/2 to 2/3 cup of walnuts to the topping for some nutty crunch.
That sounds great!
I found this on Pinterest.
I’ve been looking for a great recipe and I can’t wait to share this one with friends! 🙂 Thanks for sharing!
What type of oats do you use with your rhubarb-oatmeal bars? Thanks.
Old-fashioned oats.
Baking these as I type and the smell is bringing my teens into the kitchen. Not sure they will make the cooling time recommended. Thanks for a great recipe!
I also would like to know what kind of oats you used….
Old-fashioned oats.
Just made these and ate one warm. Delicious !
Delicious! I put all the layers in at once, after getting distracted. It was still great. Now I know what to do with all the rhubarb I’ve had gifted to me! Thank you!
Thank you so much for another inspiring recipe. I made this for dessert tonight and it was a huge success!
I’m so happy to hear everyone is loving these! I have some rhubarb in the freezer and was just thinking it’s been too long since I’ve made this. I’ll have to make a batch soon!
Can these be frozen at any point? I need to make these about 5 day ahead.
I’ve never tried freezing them. My guess is that the crumb topping would get soggy after thawing out from the freezer. If you try it, let me know how it goes!
Fabulous – after reading the reviews about them being crumbly I made them in little cake cases, worked petfectly.
Have you ever made these with rhubarb and strawberries? I’m going to be trying these very soon!
Not this particular recipe – if you add fresh strawberries, it might make the filling too juicy, which is why I use strawberry jam to add strawberry flavor, without the excess water of fresh strawberries. I did just post a new recipe a couple of days ago for strawberry bars – they’re incredible!
https://curlygirlkitchen.com/brown-butter-strawberry-cardamom-crumb-bars/
Just made this—wonderful! I'm always trying to boost health—so I substituted 1/2 flour with buckwheat/ground flax and added chia seed and turmeric to middle layer. Did not have strawberry jam, but used raspberry and it was delightful substitution.
Those additions sound delicious!
So basically you pretty much changed the whole recipe and made your own recipe, that’s great!!!
These bars were the best! Will not change a thing and WILL be making them again SOON!
My sister-in-law made these and I was addicted! Later, I made them for a large family get together and was told they are the most perfect dessert bar ever- and that includes chocolate. They ate more of the rhubarb bars than the lemon bars and Rice Krispy bars combined! After that, I planted rhubarb in my garden.
I’m so happy to hear that! 🙂
Hi Heather,
Can this recipe be doubled to folio a 9×13 pan or will it not cook properly in the middle?
It would probably be fine, but I haven’t tested a double batch. Let me know how it goes!
Made these, liked very much as I always need ways to use my rhubarb. Shared with friends who liked too. I only wished for less bottom crust and more filling. Next time will use less of the crust mixture.
I live at sea level, and this turned out pretty well. However, it seemed like there was too much butter, so I would probably decrease it by 1/4 cup or more if I make it again. I loved the use of strawberry jam instead of strawberries! 🙂