Looking for a dessert that’s fruity, slightly tart, and irresistibly crumbly? These Very Berry Rhubarb Bars are the answer. Combining the sweet tang of rhubarb with a colorful mix of berries and a buttery oat crumb crust, these bars are a perfect way to welcome spring and summer flavors into your kitchen. They’re just the right balance of bright fruit and comforting crumble, ideal for potlucks, picnics, or simply satisfying your sweet tooth.

With a golden crust and topping sandwiching a juicy fruit layer, these bars are simple to prepare yet impressive to serve. Rhubarb's tangy snap complements the natural sweetness of berries, while the lemon and vanilla bring everything together beautifully. They make a refreshing dessert in the warmer months and are a delightful alternative to heavy cakes or pies.

Whether you serve them as an afternoon snack with tea, pack them in lunchboxes, or enjoy them as a casual treat after dinner, these bars are always a hit. Best of all, they slice into neat, portable squares that are as easy to share as they are to love. One batch goes a long way, and they keep well in the fridge for days of snacking.

Why You’ll Love Very Berry Rhubarb Bars

Fruit-packed: A delicious mix of rhubarb and berries for flavor and color.
Crisp and crumbly: Buttery oat crust with a tender fruit center.
Simple ingredients: Made from pantry and fridge staples.
Portable and sharable: Perfect for gatherings or lunchbox treats.
Customizable: Use your favorite berry blend or switch up the fruit.
Make-ahead friendly: Can be baked, cooled, and stored in advance.
Visually stunning: The vibrant fruit colors shine through every layer.

Ingredients You’ll Need

1 cup all-purpose flour
½ cup rolled oats
½ cup packed brown sugar
½ teaspoon baking soda
¼ teaspoon salt
½ cup unsalted butter, melted
1 ½ cups rhubarb, diced
1 cup mixed berries (strawberries, raspberries, blueberries)
¼ cup granulated sugar
2 teaspoons cornstarch
1 tablespoon lemon juice
1 teaspoon vanilla extract

Step-by-Step Instructions

Preheat and prepare pan:
- Preheat your oven to 350°F (175°C).
- Grease or line an 8x8-inch baking pan with parchment paper for easy removal.
Make the crust and topping:
- In a medium bowl, mix together the flour, oats, brown sugar, baking soda, and salt until evenly combined.
- Add melted butter and stir with a fork or spatula until the mixture becomes crumbly but moist.
- Press about ⅔ of the crumb mixture firmly into the bottom of the prepared pan, forming an even crust layer.
Prepare the fruit filling:
- In a separate bowl, combine the diced rhubarb and mixed berries.
- Add the granulated sugar, cornstarch, lemon juice, and vanilla extract.
- Toss gently until all the fruit is coated and the cornstarch is well distributed.
Assemble the bars:
- Spread the fruit mixture evenly over the pressed crust layer.
- Use a spoon or your hands to sprinkle the remaining crumb mixture evenly over the fruit.
- Lightly pat the topping down so it adheres to the fruit but still remains loose and crumbly.
Bake:
- Place the pan in the preheated oven and bake for 35–40 minutes.
- The top should be golden brown and the fruit should be bubbly and juicy at the edges.
Cool and slice:
- Allow the bars to cool completely in the pan—this may take 1 to 2 hours.
- Once cooled, lift them out using the parchment paper and cut into 9 or 12 bars.
- Wipe the knife clean between cuts for sharp, neat squares.

Serving and Storage Tips

Serve these bars slightly chilled for a firmer texture or at room temperature for a softer bite. For an extra indulgent touch, top each bar with a scoop of vanilla ice cream, a swirl of whipped cream, or a drizzle of yogurt glaze. They pair wonderfully with a hot cup of coffee or a refreshing iced tea.

Store leftover bars in an airtight container in the refrigerator for up to 5 days. To freeze, wrap each bar individually in plastic wrap and store in a freezer-safe container for up to 2 months. Defrost overnight in the fridge and enjoy cold or briefly warmed in the microwave.

These bars travel well, making them great for lunchboxes, road trips, and potlucks. They also make a lovely homemade gift when wrapped in parchment and tied with twine.

Helpful Notes

Berry options: Use any combination of fresh or frozen berries, but drain any excess liquid if using frozen to avoid soggy bars.
Thicker crust: For a heartier base, increase the portion of crumb mixture used on the bottom to ¾.
Flavor add-ins: Add a pinch of cinnamon or nutmeg to the crust mixture for warm spice.
Lining the pan: Parchment paper with overhang on the sides makes lifting and cutting easier.
Extra sweetness: Sprinkle coarse sugar or turbinado sugar on top before baking for added crunch and sparkle.

Frequently Asked Questions

Can I use only rhubarb or only berries? Yes! If using only rhubarb, increase the sugar to balance its tartness. If using only berries, reduce the sugar slightly if they are very sweet.
Can I make this gluten-free? Absolutely. Substitute the flour with a 1:1 gluten-free baking blend and use certified gluten-free oats.
Do I need to cook the filling first? No need! The fruit softens and the filling thickens perfectly as it bakes in the oven.
Can I double the recipe? Yes! Simply double all the ingredients and bake in a 9x13-inch pan. Extend the baking time by 5–10 minutes and check for doneness.
What if I don’t have lemon juice? You can substitute with orange juice or a splash of apple cider vinegar for acidity.

Final Thoughts

Very Berry Rhubarb Bars are everything you want in a fruity dessert: tart, sweet, buttery, and perfectly portable. With a crisp oat crust and vibrant fruit filling, they’re a joy to make and even better to eat. These bars are a seasonal favorite that highlight the best of what spring and summer have to offer.

Whether you're baking for guests, preparing for a picnic, or just treating yourself to something homemade and delicious, this recipe delivers every time. Make a batch, savor the aroma, and enjoy a dessert that tastes as good as it looks!

Very Berry Rhubarb Bars

Emily

These Very Berry Rhubarb Bars combine the tartness of rhubarb with the sweetness of mixed berries, all atop a buttery oat crust. Perfect for spring gatherings or a delightful dessert any time!

Print Recipe Pin Recipe

Prep Time 15

Cook Time 40

Total Time 55

Servings 9 bars

Calories 210 kcal

Ingredients

1 cup all-purpose flour
½ cup rolled oats
½ cup packed brown sugar
½ teaspoon baking soda
¼ teaspoon salt
½ cup unsalted butter melted
1 ½ cups rhubarb diced
1 cup mixed berries strawberries, raspberries, blueberries
¼ cup granulated sugar
2 teaspoons cornstarch
1 tablespoon lemon juice
1 teaspoon vanilla extract

Instructions

Preheat oven to 350°F (175°C). Grease or line an 8x8-inch baking pan with parchment paper.
In a medium bowl, combine flour, oats, brown sugar, baking soda, and salt. Stir in melted butter until the mixture is crumbly.
Press ⅔ of the crumb mixture firmly into the bottom of the prepared pan to form the crust.
In another bowl, toss together diced rhubarb, mixed berries, granulated sugar, cornstarch, lemon juice, and vanilla extract until evenly coated.
Spread the fruit mixture evenly over the crust.
Sprinkle the remaining crumb mixture on top of the fruit layer.
Bake for 35–40 minutes, or until the top is golden and the fruit filling is bubbling.
Let cool completely before cutting into bars.

Notes

For a thicker crust, use more than ⅔ of the crumb mixture for the base.
If using frozen berries, thaw and drain excess liquid to prevent sogginess.
Store bars in an airtight container in the refrigerator for up to 5 days.
Bars can be frozen for up to 2 months; thaw in the refrigerator before serving.