Strawberry Rhubarb Crumble Bars are the perfect mix of sweet and tangy, with a buttery crumbly crust that holds everything together. The juicy strawberries and tart rhubarb create a fantastic combo that feels like summer in every bite. It’s the kind of treat that’s both fresh and comforting at the same time.
I love making these bars when I want something that’s a little different from your usual cookie or pie. The crumble topping adds a nice crunch, and the filling is just the right balance of juicy and tart. I usually make a big batch because they disappear fast—everyone always asks for more!
These bars are great for packing in a lunchbox or taking to a casual get-together. I like to serve them slightly warm or at room temperature, and honestly, they’re fantastic just as they are, no fuss needed. If you’re looking for a simple, happy dessert that brings a bit of sunshine, these crumble bars are a winner every time.
Key Ingredients & Substitutions
Rhubarb: Rhubarb’s tartness is what makes these bars special. If you can’t find fresh rhubarb, frozen works fine, just thaw and drain it well to avoid extra moisture.
Strawberries: Fresh, ripe strawberries bring sweetness and color. If strawberries aren’t in season, try frozen berries or swap with raspberries for a similar tart-sweet punch.
Rolled Oats: Oats add texture and heartiness to the crust and topping. If you don’t have oats, you can use all flour, but the bars will be less crumbly.
Butter: Butter is key for that rich, buttery crumb. You can use margarine or coconut oil in equal amounts for a dairy-free option, but flavor will vary slightly.
How Do You Get the Perfect Crumble Texture?
Making the crumble just right means a good balance between crumbly and holding together. Here’s how:
- Mix dry ingredients with melted butter until you have coarse crumbs. Don’t overmix or the crust can become tough.
- Press two-thirds firmly into the pan for a sturdy base.
- Sprinkle the remaining crumb topping loosely over the fruit, so it crisps up nicely during baking.
- Bake until golden brown and bubbling, then cool completely so the filling sets and bars cut cleanly.
Patience with cooling really helps the bars keep their shape while keeping the crumb layers deliciously crumbly.
Equipment You’ll Need
- 9×9-inch baking pan – I use this size for even cooking and easy slicing of the bars.
- Mixing bowls – for combining the dry ingredients and fruit filling easily.
- Rubber spatula – helps spread the crust evenly and mix ingredients smoothly.
- Measuring cups and spoons – for accuracy when adding ingredients.
- Parchment paper – makes it simple to lift the bars out of the pan and keeps cleanup easy.
Flavor Variations & Add-Ins
- Swap strawberries for raspberries or blueberries for a different, tangy twist.
- Mix in chopped nuts like pecans or walnuts on top of the crumble for extra crunch.
- Add a splash of lemon juice or zest to the fruit filling for a bright flavor boost.
- Use a crumbly almond or oatmeal topping instead of the standard for a different texture and taste.
Strawberry Rhubarb Crumble Bars
Ingredients You’ll Need:
For The Crust and Crumble:
- 1 1/2 cups all-purpose flour
- 1 cup rolled oats
- 1 cup granulated sugar, divided
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 3/4 cup unsalted butter, melted
For The Filling:
- 2 cups diced rhubarb
- 2 cups chopped fresh strawberries
- 1 tablespoon cornstarch
- 1 teaspoon vanilla extract
Optional Topping:
- Powdered sugar, for dusting
How Much Time Will You Need?
Prepare for about 15 minutes of prep time plus 45-50 minutes baking. Then you’ll want to let the bars cool completely, about 1 hour, to help the filling set well before cutting and serving.
Step-by-Step Instructions:
1. Get Ready:
Preheat your oven to 350°F (175°C). Line a 9×9-inch baking pan with parchment paper, leaving extra on the sides to lift the bars out easily later.
2. Make Your Crust and Crumble:
In a large bowl, mix the flour, oats, 3/4 cup sugar, baking soda, and salt. Pour in the melted butter and stir until you get a crumbly mixture that just holds together when pressed.
Take about two-thirds of this mixture and press it firmly and evenly into the bottom of your prepared pan to make the crust layer.
3. Prepare The Filling:
In a separate bowl, combine the diced rhubarb, chopped strawberries, the remaining 1/4 cup sugar, cornstarch, and vanilla extract. Toss everything gently to coat the fruit well and help thicken the filling as it cooks.
Spread this fruity mixture evenly over the crust in your pan.
4. Add The Crumble Topping:
Sprinkle the remaining oatmeal crumb mixture evenly over the fruit layer. It can be a little loose—that’s perfect for a crisp, buttery topping.
5. Bake And Cool:
Bake your bars for 45 to 50 minutes, until the topping is beautifully golden and the fruit filling bubbles up around the edges.
Once baked, remove the pan from the oven and set it on a wire rack. Let your bars cool completely in the pan so the filling sets up nicely—this usually takes about an hour.
6. Serve And Enjoy:
Use the parchment paper edges to carefully lift the entire slab out of the pan. Cut into squares or rectangles.
If you like, dust the bars with powdered sugar for a sweet and pretty finish before serving. These bars are wonderful at room temperature or gently warmed.
Can I Use Frozen Strawberries and Rhubarb?
Yes, you can use frozen fruit! Just be sure to thaw and drain any excess liquid to prevent the bars from becoming soggy.
How Should I Store Leftover Bars?
Store the bars in an airtight container at room temperature for up to 2 days, or refrigerate for up to a week. They also freeze well—wrap tightly and thaw before serving.
Can I Substitute the Oats?
If you don’t have rolled oats, you can use quick oats or increase the flour slightly, but the texture will be less crumbly and more cake-like.
How Do I Make the Bars Less Tart?
To reduce tartness, add a bit more sugar to the filling or include a splash of honey or maple syrup when mixing the fruit.