Rhubarb Crumble Bars

When rhubarb is in season, Rhubarb Crumble Bars are the perfect treat. They’re easy to make and very tasty. Buttery oatmeal crust is layered with sweet-tart rhubarb filling and topped with chunky brown sugar topping.

rhubarb crumble bars

Sometimes, even the simplest recipes take several tries to get it exactly right. This is one of those recipes.

As soon as I see rhubarb in the local market I buy a big bunch before I even know what I’m going to do with it. It doesn’t matter. I love rhubarb so much that I buy it first and figure out what to do with it later.


  • Rhubarb – Choose rhubarb that is plump and crisp.
  • Granulated sugar – Rhubarb needs sugar to tame the tart flavor.
  • Vanilla extract – Enhances the filling and the crumb.
  • All purpose flour/Old fashioned rolled oats – The flour and oat together form the structure of the cookie base and the crumb topping.
  • Baking soda – For a little lift in the cookie base.
  • Salt/cinnamon – For flavor
  • Brown sugar – Brown sugar adds a butterscotch flavor to the cookie crumble.
  • Unsalted butter – Butter brings the crumble together.

Why you’ll love these Rhubarb Crumble Bars

I have a tried and true Raspberry Bar recipe that I’ve used for years. I assumed it would be easy enough to simply replace the raspberry jam with rhubarb and call it a day. Well, you know what they say, never assume…

I made a quick rhubarb filling and layered it with my chunky, brown sugar/oatmeal crumble. I baked it up, and the bars tasted good. I mean, they were just fine.

But, just fine isn’t good enough. I wasn’t quite happy with the recipe. The rhubarb got a little lost in the crust, and this recipe is all about the rhubarb.

I can tell you that I don’t phone it in. I really want a recipe to be the best possible version before I post it for you. So, as tempted as I was to post the recipe without making it again, I had to give it another go.

Since the rhubarb was melding into the crust, I decided to bake the bottom crust before adding the rhubarb. I hoped that would keep the rhubarb layer intact.

It worked. The second batch of bars was much better. The bottom crust is crunchy and the rhubarb layer is very distinct. Sometimes, just a small tweak makes all the difference.

Watch the recipe video to see how to make Rhubarb Crumble Bars.

I am obsessed with the unique flavor of rhubarb. You too? Here are a few more recipes for you to try:

Here are a few more fruit and crumb bar recipes: Peanut Butter & Jelly Crumb Bars, Blueberry Crumb Bars.

If you love this recipe as much as I do, I’d really appreciate a 5-star review.

a stack of rhubarb crumble bars
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4.56 from 27 reviews

Rhubarb Crumble Bars Recipe

Buttery oatmeal crust is layered with sweet-tart rhubarb filling and topped with chunky brown sugar topping. When rhubarb is in season, this is the perfect treat that is easy to make and very tasty.
Prep Time30 minutes
Bake Time35 minutes
Total Time1 hour 5 minutes
24 bars
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For the Filling

  • 24 oz rhubarb
  • 6 oz sugar (¾ cup)
  • ¼ teaspoon table salt
  • 1 teaspoon vanilla extract

For the dough

  • 10 oz all purpose flour (2 cups, see note)
  • 6 ½ oz old fashioned rolled oats (2 cups)
  • ½ teaspoon baking soda
  • ½ teaspoon salt
  • ½ teaspoon cinnamon
  • 8 oz brown sugar (1 cup)
  • 4 oz granulated sugar (½ cup)
  • 1 teaspoon vanilla extract
  • 12 oz unsalted butter (sliced)


Make the filling

  • Slice the rhubarb into ½" thick slices and toss with 6 oz sugar and ¼ teaspoon table salt in a large saucepan. Cover the pan and set the rhubarb aside for 30 minutes to 1 hour to macerate.
  • Cook the rhubarb over medium heat until boiling. Reduce heat and simmer 5-10 minutes until most of the rhubarb is tender and it’s beginning to thicken. You’ll have about 3 cups of rhubarb filling.
  • Transfer to rhubarb to a bowl, stir in 1 teaspoon vanilla extract and cool to room temperature.

Make the Dough

  • Preheat the oven to 350 °F. Generously butter a 13" x 9" pan. Line the pan with parchment paper for easier removal of the bars (optional).
  • Combine 10 oz all purpose flour, 6 ½ oz old fashioned rolled oats, ½ teaspoon baking soda, ½ teaspoon salt, ½ teaspoon cinnamon, 8 oz brown sugar, 4 oz granulated sugar1 teaspoon vanilla extract in a large mixing bowl. Mix to combine the ingredients.
  • Toss in 12 oz unsalted butter and mix with your fingers until the butter bits are no larger than a pea and the dough clumps together when squeezed.
  • Reserve 1/3 of the dough for the topping. Sprinkle the remaining 2/3 of the dough into the pan and and press into an even layer. Bake 10 minutes until set and just beginning to brown.
  • Spread the rhubarb filling over the crust and crumble the remaining dough over the filling. Bake until golden brown, about 20-25 minutes
  • Cool completely and cut into bars.

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If measuring the flour by volume use the “dip & sweep” method. That is, dip the measuring cup into the flour bin, overfill it, then sweep away the excess.
The butter should be slightly cool, but a little pliable. If the butter is very cold it will be more difficult to cut it into the dry ingredients. If the butter is very soft, it will completely mix in and you won’t get nice large clumps of crumbs.
This recipe can be halved and baked in a 9″x9″ square pan.


Serving: 24slice | Calories: 262kcal | Carbohydrates: 37g | Protein: 3g | Fat: 12g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.5g | Cholesterol: 30mg | Sodium: 102mg | Potassium: 139mg | Fiber: 2g | Sugar: 21g | Vitamin A: 383IU | Vitamin C: 2mg | Calcium: 42mg | Iron: 1mg
Have you tried this recipe?Mention @eileen.bakingsense or tag #bakingsense!

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