Strawberry Rhubarb Crumble Bars are a perfect blend of sweet and tangy with a crumbly, buttery crust that you can’t resist. These bars bring together the bright, juicy flavor of strawberries and the tart bite of rhubarb, all topped with a golden, crumbly layer that adds just the right crunch. It’s a simple, homey dessert that feels just right for any time you want a little something sweet with a fresh fruit twist.
I love making these bars because they’re so easy to share — I often cut them into small squares for parties or to pack in lunchboxes. The mix of sweet strawberries and tart rhubarb always surprises people in the best way. Plus, that crumble on top? It’s my favorite part, especially when it turns golden brown and crunchy in the oven. I usually make a double batch because they disappear fast!
These bars are great served just as they are, but I also like to warm them up slightly and add a scoop of vanilla ice cream on top. It’s like an instant little treat that can brighten up any day. They remind me of sunny afternoons spent in the kitchen, making something simple and special for family and friends to enjoy together.
Key Ingredients & Substitutions
Butter: Butter adds a rich, buttery flavor and helps create the crisp crumble texture. If you want a dairy-free option, try using coconut oil or a vegan butter substitute, but the flavor and texture will change slightly.
Old-Fashioned Rolled Oats: These give the crumble its nice chew and heartiness. Quick oats are a possible substitute but may make the topping less textured and more soft.
Strawberries & Rhubarb: Fresh is best for bright flavor and texture here. If fresh rhubarb is not available, frozen works too—just thaw and drain well. You can swap strawberries for raspberries or cherries for a different fruit twist.
Cornstarch: This thickens the juicy fruit filling so it’s not runny. If you don’t have cornstarch, arrowroot or tapioca starch are good alternatives.
How Do I Get the Perfect Crumble Texture?
The crumble topping is what makes these bars extra special. The key is to mix the butter and dry ingredients until crumbly but with some small pea-size chunks for texture.
- Start with melted butter, then stir in sugar and dry ingredients until combined but crumbly.
- Reserve some mixture for topping before pressing the rest firmly for the crust.
- Sprinkle the leftover crumble loosely on top rather than pressing it down; this helps it stay light and crisp.
- Watch the bars near the end of baking. When the topping turns golden brown and the fruit is bubbling, it’s done!
Equipment You’ll Need
- 9×13-inch Baking Pan – I like this size because it’s just the right thickness for bars without crowding.
- Mixing Bowls – You’ll need one for the crust and topping, and another for the fruit filling—big enough to stir everything comfortably.
- Measuring Cups and Spoons – Accurately measure ingredients for the best results; I always use a set with clear markings.
- Spatula or Wooden Spoon – For mixing the crumble topping and fruit filling smoothly.
- Parchment Paper (optional) – Lining the pan makes cleanup easier and helps lift out the bars neatly.
Flavor Variations & Add-Ins
- Swap Rhubarb with Cherries or Raspberries for a different tartness and color — they pair well with strawberries.
- Add a pinch of cinnamon or ginger to the crumble for warm, spiced flavor notes.
- Mix chopped nuts (like almonds or pecans) into the crumble topping for extra crunch and flavor.
- Use lemon zest in the fruit filling to boost the brightness and add a fresh citrus aroma.
Strawberry Rhubarb Crumble Bars
Ingredients You’ll Need:
For the Crust and Crumble:
- 1 cup (2 sticks) unsalted butter, melted
- 1 cup granulated sugar
- 2 cups all-purpose flour
- 2 cups old-fashioned rolled oats
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
For the Filling:
- 2 cups fresh strawberries, chopped
- 2 cups fresh rhubarb, chopped
- 3/4 cup granulated sugar
- 2 tablespoons cornstarch
- 1 teaspoon vanilla extract
- 1 tablespoon lemon juice
How Much Time Will You Need?
This recipe takes about 15 minutes to prep and 45 to 55 minutes to bake. After baking, allow the bars to cool completely, which will take another 30 minutes or so. Overall, set aside about 1.5 hours from start to finish.
Step-by-Step Instructions:
1. Get Ready:
Heat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper or lightly grease it so the bars don’t stick.
2. Make the Crumble Mix:
In a large bowl, stir melted butter and sugar together until smooth. Add flour, oats, baking soda, and salt. Mix well until the texture looks crumbly. Take about 1 1/2 cups of this mixture out and set it aside for the topping later.
3. Press the Crust:
Press the rest of the crumb mixture firmly and evenly into the bottom of your baking pan to form the crust layer. Make sure it’s packed well – this will be the base of your bars.
4. Prepare the Filling:
In another bowl, combine the chopped strawberries, rhubarb, sugar, cornstarch, vanilla extract, and lemon juice. Stir until all the fruit is coated and the cornstarch is completely dissolved.
5. Assemble the Bars:
Spread the fruit filling evenly over the crust. Then, sprinkle the set-aside crumble mixture evenly on top of the fruit layer – this will be your crunchy topping.
6. Bake:
Place the pan in the oven and bake for 45 to 55 minutes. The top should turn golden brown, and you should see the filling bubbling around the edges.
7. Cool and Serve:
Remove the bars from the oven and let them cool completely in the pan on a wire rack. Once cool, lift them out using the parchment paper edges and cut into squares. Enjoy your delicious strawberry rhubarb crumble bars!
Can I Use Frozen Strawberries and Rhubarb?
Yes! Just make sure to thaw them completely and drain any excess liquid before mixing the filling to avoid a soggy crust.
How Should I Store Leftover Bars?
Store leftovers in an airtight container at room temperature for up to 2 days or in the fridge for up to 5 days. You can also freeze the bars for up to 3 months—just thaw before serving.
Can I Substitute the Oats in the Crumble?
If you’re avoiding oats, you can replace them with extra flour or crushed nuts for crunch, but the texture will be a bit different.
Is There a Way to Make the Bars Less Sweet?
You can reduce the sugar in the filling by about a quarter cup if you prefer a tarter taste, especially since rhubarb is naturally tart.