Rhubarb Crumble Bars

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.

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

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• Author: Delphine Fortin
• 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

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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

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Instructions

1. Preheat the oven to 400°F (200°C) and grease a 9-inch square pan. Set aside.

For the base:

1. 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.
2. Transfer the dough to the pan in a thick layer, covering all parts of the bottom of the pan.

For the rhubarb compote:

1. 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.
2. Let cool for 5 minutes, then pour over the base in the pan.

For the crumble topping:

1. Mix all the ingredients together and sprinkle over the rhubarb compote.
2. Bake for about 20-25 minutes, until the top is slightly golden. Let cool completely, then share in square, and enjoy!

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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!