Raspberry and Rhubarb Crumble Bars

Tangy and sweet, these bars combine a walnut crumble topping with a ruby-red raspberry and rhubarb filling in a delicious bite-sized package.

Lately, I’ve been spending a lot of time puttering around in the garden, taking advantage of having all this extra time at home and doing my best to channel my grandmother’s green thumb.

My grandmother’s skill with growing food was pretty much magical, or at least that’s how it seemed to be when I was growing up.

Her ability to grow things was legendary. She could cut up potatoes from the store and dig up a fresh crop of baby potatoes a few short weeks later, and grew the most delicious green beans I’ve ever had. Her magic touch even worked indoors, coaxing even the most temperamental of African violets to re-bloom.

And now that I have a home of my own, I’ve tried to carry on a small part of that legacy with my little garden patch.

It’s not much, but I’ve filled the garden beds with green beans, carrots, cucumbers, squash, and salad greens, and decorated the deck with pots full of herbs, radishes and hot peppers to help spice up our meals.

Rhubarb and Raspberries – A Perfect Match

These old-fashioned crumble bars showcase two other crops from my garden in their bright ruby-red filling – raspberries and rhubarb.

My backyard raspberry patch has been loving the hot summer weather and non-stop sunshine and has delivered a bumper crop so plentiful that I don’t even know what to do with it all.

The rhubarb has been a little more restrained, but I’ve still been able to harvest enough to make a batch of these bars, which is a perfectly good showing for a three-year-old plant.

The combination perfectly encapsulates the flavors of the season. It’s fresh and jammy and bright, a tangy counterpoint to the buttery sweetness of the oatmeal crumble that does double duty as both the base and topping. A sprinkling of chopped walnuts is entirely optional, but oh so delicious.

Technically, these are intended for dessert, but I think they’re perfectly suitable for breakfast too. I mean, aren’t they just a fancier version of a bowl of oatmeal with a raspberry and rhubarb topping? (OK, I know that’s a stretch, but at times like these, we could all use a little extra treat.)

Variations on this Recipe

While I like to think this particular combination is pretty dang close to perfection, there are a few different ways to play around with this recipe depending on what you’ve got kicking around.

  • Strawberry-Rhubarb Bars: Simply replace the raspberries with the same amount of roughly chopped fresh strawberries, and continue on from there. The end result isn’t quite as tangy or intensely colored, but it’s still got plenty of fruity brightness.
  • Raspberry-Almond Bars: Omit the rhubarb and use 3 cups of raspberries, add a ½ tsp almond extract to the crumble mixture, and replace the chopped walnuts with ½ cup sliced blanched almonds.
  • Bumbleberry Bars: Replace the raspberries and rhubarb with 3 cups frozen mixed berries, or make your own blend using raspberries, blueberries, blackberries, cherries, strawberries and/or any other berry that catches our fancy.

Raspberry and Rhubarb Crumble Bars

Recipe by IsabelleCourse: DessertCuisine: CanadianDifficulty: Easy


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Tangy and sweet, these bars combine a walnut crumble topping with a ruby-red raspberry and rhubarb filling in a delicious bite-sized package.


  • For the filling:
  • 1 ½ cups of rhubarb, cut into ½” pieces

  • 1 ½ cups of fresh or frozen raspberries

  • ½ cup of sugar

  • 2 tbsp of lemon juice

  • 1 ½ tbsp of cornstarch

  • For the crumble crust:
  • 1 ¼ cup of flour

  • ½ cup of quick oats

  • ½ cup of brown sugar

  • ½ tsp of salt

  • ½ tsp of baking powder

  • ½ tsp of cinnamon

  • ½ cup of butter, melted

  • ½ cup of chopped walnuts


  • Preheat the oven to 350F. Lightly butter an 8×8″ square pan and line with a piece of parchment paper, leaving an overhang on either side. Lightly butter the parchment. Set aside.
  • Prepare the filling. In a small saucepan set over medium heat, bring the filling ingredients to a simmer. Cook, stirring occasionally, for about 10 minutes or until the filling is thickened and rhubarb is starting to break down. Remove from heat and set aside to cool.
  • Meanwhile, prepare the crumble crust. In a large mixing bowl, combine flour, oats, sugar, salt, baking powder and cinnamon. Drizzle in the melted butter, and stir until the mixture forms loose crumbs.
  • Set aside 1 cup of the mixture for the topping. Press the remainder into the prepared baking pan, using the bottom of a glass or measuring cup to form an even layer. Spread the cooled filling onto the crust. Crumble the reserved topping evenly onto the filling, then scatter chopped walnuts over top.
  • Bake in preheated oven for 30-35 minutes, or until the filling is bubbly around the edges and the topping is lightly golden. Let cool completely in the pan, then transfer to a cutting board and cut into 12 bars. Bars will keep for up to 3 days in an airtight container (assuming they actually last that long).

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