Easy Rhubarb Crumble Bars
These incredibly easy rhubarb crumble bars are my go-to dessert this season. If you’ve been following my blog, you know my love for rhubarb runs deep—deep enough that I once told our closing title company here in South Dakota that rhubarb was my main reason for moving here (true story, no shame!). Growing up, rhubarb was a summer staple, starring in everything from sauces and pies to slushies and muffins. I can’t get enough rhubarb treats I have even more family-favorite recipes to share with you.
Today, I’m thrilled to share an updated version of my classic rhubarb bars, a recipe I originally posted years ago. The old recipe was delicious but designed for a larger 9×13-inch pan with a crust that was overly sweet. After some tweaking, I’ve scaled it down to a 9×9-inch pan for a smaller batch. I also boosted the crumble for a chunkier texture, increased the filling for more rhubarb goodness, and reduced the sweetness to let that tart rhubarb shine. Since the rhubarb filling is cooked to a thick, jam-like consistency on the stovetop, it bakes up perfectly without a soggy crust. These easy rhubarb crumble bars are still no-fuss, with that perfect tart-sweet-oatmeal balance, but now they’re even better—crumbly, structured, and downright irresistible, even for rhubarb skeptics.
Why You’ll Love These Rhubarb Crumble Bars
- Crowd-Pleaser: Even rhubarb skeptics love these tart rhubarb oatmeal bars, thanks to their crisp texture and balanced flavor.
- Perfect Tart-Sweet Balance: The reduced sugar lets rhubarb’s natural tang shine, complemented by a just-sweet-enough oatmeal crumble.
- Chunky, Buttery Crumble: A thicker, rustic crumble replaces the dense crust, with generous layers for both base and topping.
- No Soggy Bottom: The stovetop-cooked rhubarb filling sets beautifully, keeping the crust crisp without prebaking.
- Easy and Versatile: Simple to make with precise measurements.
What’s Changed from the Original?
If you loved my original rhubarb bars (made for a 9×13 pan with less rhubarb and a cakier crust), here’s how these easy rhubarb crumble bars level up:
- Smaller Pan, Better Balance: Scaled down to a 9×9-inch pan for a cozier batch, with a slightly increased filling for more tart flavor.
- Chunkier Crumble: The crust and topping are now a rustic, buttery crumble instead of a more cake-like creamed crust, giving a thicker base and generous topping.
- Less Sweet: Reduced sugar in both filling and crumble to highlight rhubarb’s natural tang.
- Precise Measurements: Added gram weights for accuracy, so every batch is perfect.
Tips for Success
- Thick Filling: Cook the filling until it’s jam-like to avoid excess liquid. If it’s still runny after cooling, drain a bit before spreading.
- Crisp Crust: The cooked filling and thicker crumble ensure a firm base, but press the crust firmly for best results.
- Customize: Add ½ tsp cinnamon to the crumble for a warm note, or swap in gluten-free flour/oats or vegan butter for dietary needs.
- Storage: These small batch rhubarb bars keep well in the fridge for 4 days or freeze for up to 3 months. Thaw and reheat at 300°F for 10 min to revive the crumble’s crunch.
Why Easy Rhubarb Crumble Bars Are a Must-Try
These bars are a love letter to rhubarb’s tart charm, with a buttery, oatmeal-packed crumble that’s just sweet enough to complement it. They’re simple to whip up, hold their shape beautifully, and win over even rhubarb doubters (trust me, I’ve tested them!). Whether you’re a rhubarb fanatic like me or just looking for a summer treat to share, these best rhubarb crumble bars are sure to become a staple in your kitchen.
Have you tried the original recipe, or are you diving into this new version? Let me know in the comments how they turn out, or share your favorite rhubarb recipes—I’d love to hear how you enjoy it! And stay tuned for more rhubarb recipes as my garden keeps growing.
Easy Rhubarb Crumble Bars
Print Recipe
Ingredients
Filling:
- 2 cups rhubarb, ¼-inch diced (about 3 stalks) (240 g)
- ¾ cup granulated sugar (150 g)
- 1 tsp vanilla extract
- 2 Tbsp cornstarch (16 g)
- 3½ Tbsp cold water (52 g)
Crumble (Crust and Topping):
- 1¼ cups quick oats (100 g)
- 1¼ cups all-purpose flour (150 g)
- ½ cup light brown sugar, packed (100 g)
- ½ tsp baking soda
- ½ tsp salt
- ¾ cup salted butter, cold & cubed (170 g)
Instructions
- Preheat Oven: Preheat to 375°F (190°C). Grease a 9×9-inch pan or line with parchment (overhang for easy removal).
- Prepare Filling: Dissolve cornstarch in cold water. In a saucepan, combine rhubarb, sugar, vanilla, and slurry. Cook over medium heat, stirring, until thick like jam (5–8 min). Cool slightly. Drain excess liquid if watery.
- Prepare Crumble: Whisk oats, flour, brown sugar, baking soda, and salt. Cut in cold butter with a pastry cutter or fingers until coarse crumbs with pea-sized pieces form.
- Assemble: Press ⅔ crumble firmly into pan’s bottom for a thick base. Spread filling evenly over crust. Sprinkle remaining ⅓ crumble loosely on top, letting some filling peek through.
- Bake: Bake 25–30 min until topping is golden and filling bubbles. Cool in pan 1–2 hours before cutting into 9 squares.
- Serve: Serve warm or at room temp. Store in fridge up to 4 days. Reheat gently if desired.
Notes
- Thick Filling: Cook until jam-like to avoid excess liquid. Drain if needed before spreading.
- Crisp Crust: Press crust firmly for a sturdy base. The cooked filling keeps it crisp.
- Customize: Add ½ tsp cinnamon or ¼ cup chopped nuts for extra flavor.
- Storage: Refrigerate for 4 days or freeze for 3 months. Thaw and reheat at 300°F for 10 min to revive crunch.
Enjoy!
As an Amazon Associate, I earn from qualifying purchases at no extra cost to you. Thank you for your support!
So simple but absolutely delicious!! Love this one.
So easy and delicious! Definitely will be repeating this one!
Great texture with perfect amount of sweetness! May try adding more rhubarb filling next time to accentuate that flavor.
Absolutely delicious!! Perfect amount of softness and texture all at the same time. Not sure about rhubarb? This will make you a fan 🙂
I personally am not a fan of rhubarb. I really, really like this bar cookie! The texture and the flavor are perfection! Very satisfying when I get a sweet craving, but now I’m going to have to find a rhubarb supply! 😁