Easy Blueberry Crumble Bars

These Blueberry Crumble Bars are your new go-to summer dessert! With a buttery, crumbly crust and topping sandwiching a juicy blueberry filling, they’re bursting with flavor and just the right amount of sweetness. I brought these to a potluck recently, and let me tell you—they were devoured in minutes. The secret? A touch of lemon that brightens the bars without overpowering them, plus a perfectly crumbly texture achieved by working cold butter into the dough just right. Whether you’re using fresh or frozen blueberries, these bars are easy to whip up and guaranteed to impress!

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Why You’ll Love These Blueberry Crumble Bars

• Simple Ingredients: Just a handful of pantry staples and blueberries!
• Bright & Balanced: Lemon juice enhances the blueberry flavor without stealing the show.
• Perfect Texture: A crisp crust and a crumbly, buttery topping make every bite irresistible.
• Potluck Superstar: Easy to transport and universally loved—I’ve seen these disappear fast!
• Versatile: Great for dessert, a snack, or even breakfast (no judgment here!).

Let’s dive into this crowd-pleasing recipe, complete with all my tips to ensure your bars turn out perfectly every time.

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Blueberry Crumble Bars Overview

This recipe has three components: a buttery crust, a juicy blueberry filling, and a crumbly topping. The crust and topping are made from the same dough, which saves time and dishes. We’ll par-bake the crust for a few minutes to ensure it stays crisp, then layer on the filling and topping before finishing the bake. The result? Golden, delicious bars that hold together beautifully.

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Ingredients for Blueberry Crumble Bars

Here’s what you’ll need—nothing fancy, just the good stuff! I’ve included weights for precision, as always.

For the Crust & Crumble Topping:

• 2 c. all-purpose flour (240g)
• 1 c. old-fashioned rolled oats (90g)
• 1 c. granulated sugar (200g)
• 1/2 tsp. baking powder
• 1/4 tsp. salt (
• 1 c. salted butter, cold and cubed (226g)
• 1 tsp. vanilla extract

For the Blueberry Filling:

• 3 c. fresh or frozen blueberries (450g)
• 1/2 c. granulated sugar (100g)
• 1 tbsp. cornstarch (8g)
• 1 tbsp. lemon juice (15g)
• 1 tsp. lemon zest, optional (2g)

Julie’s Tip: Don’t have a kitchen scale? Spoon and level your flour to avoid packing in too much, which can make the crust dense. If using frozen blueberries, no need to thaw—just give them a quick rinse to remove any ice crystals.

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How to Make Blueberry Crumble Bars

This recipe comes together in just a few steps. The key is keeping that butter cold for the ultimate crumbly texture—don’t skip cubing it straight from the fridge!

Preheat & Prep:

1. Preheat your oven to 350°F (175°C) and place a rack in the center. Line an 8×8-inch or 9×9-inch metal baking pan with parchment paper, leaving some overhang for easy removal. Lightly grease the parchment to be safe. (Metal pans help the crust crisp up better than glass!)

For the Crumble Topping:

1. Make the Crust & Crumble Mixture:
   In a large bowl, whisk together 2 c. all-purpose flour (240g), 1 c. rolled oats (90g), 1 c. granulated sugar (200g), 1/2 tsp. baking powder, and 1/4 tsp. salt. Add 1 c. cold, cubed salted butter (226g) and 1 tsp. vanilla extract. Using a pastry cutter, two forks, or your fingers, work the butter into the dry ingredients until the mixture looks like coarse crumbs—think wet sand with some pea-sized butter bits. This step is crucial for that beautiful crumbly top, so take your time to get it right.
2. Par-Bake the Crust:
   Press about two-thirds of the mixture (around 400-450g) firmly into the bottom of the prepared pan. Use the bottom of a measuring cup to pack it down evenly—this ensures a sturdy base that won’t turn soggy. Bake the crust alone for 10 minutes to set it, then remove from the oven.

Blueberry Filling:

1. In a medium bowl, gently toss 3 c. blueberries (450g) with 1/2 c. granulated sugar (100g), 1 tbsp. cornstarch, 1 tbsp. lemon juice, and 1 tsp. lemon zest (optional BUT I HIGHLY recommend it). The cornstarch thickens the filling, while the lemon juice and zest elevate the berries, giving them a bright, fresh flavor that’s not overpowering at all.

Assembly, Bake & Serve:

1. Spread the blueberry filling evenly over the par-baked crust. Sprinkle the remaining crumble mixture (about 150-200g) loosely over the top—don’t press it down, as you want it to stay nice and crumbly. Some blueberries peeking through add a gorgeous pop of color.
2. Bake for 40-45 minutes, until the topping is golden brown and the filling is bubbling around the edges. If using frozen berries, it might take a couple of extra minutes. You’re looking for that perfect golden hue—don’t pull them out too early!
3. Let the bars cool completely in the pan, about 2-3 hours, to set the filling. (If you’re impatient like me, pop them in the fridge after an hour at room temp to speed things up.) Use the parchment overhang to lift the bars out, then slice into 12-16 squares.

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Julie’s Success Tips

• Keep the Butter Cold: Cold butter is non-negotiable for that flaky, crumbly texture. Cube it right out of the fridge and work quickly to keep it chilled. This is what makes the topping so irresistible!
• Par-Baking is Key: That quick 10-minute bake for the crust ensures it holds up against the juicy filling, giving you a crisp base every time.
• Lemon’s Magic Touch: The lemon juice and zest (if you use it) don’t make these bars taste lemony—they just brighten the blueberries, making them taste fresher and more vibrant.
• Frozen vs. Fresh Berries: Both work beautifully! If using frozen, rinse off any ice and pat dry to avoid extra moisture, but don’t thaw them fully.
• Make Ahead: These bars are perfect for prepping in advance. Bake them the day before your event—they hold up wonderfully!

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How to Store Blueberry Crumble Bars

Store the bars in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days. They also freeze like a dream—wrap individual bars tightly in plastic wrap and store in a freezer-safe bag for up to 3 months. Thaw at room temp or warm in the microwave for a just-baked vibe.

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Serving Suggestions

These bars are fantastic on their own, but if you want to take them over the top, serve them warm with a scoop of vanilla ice cream or a dollop of whipped cream. They’re also sturdy enough to pack for picnics, potlucks, or lunchbox treats. I brought mine to a potluck, and they vanished before I could grab seconds—consider that your warning to stash one for yourself!

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Frequently Asked Questions

Can I use other berries?
Absolutely! Raspberries, blackberries, or a mixed berry combo would be delicious. Just keep the total weight around 450g.

Can I reduce the sugar?
You can cut the sugar in the filling to 1/3 c. (67g) if your berries are super sweet, but the crust/topping needs the full amount for structure and texture.

Why par-bake the crust?
Par-baking sets the base, preventing it from getting soggy under the juicy filling. It’s a small step that makes a big difference!

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Try These Next

Loved these bars? Here are more crowd-pleasing treats to bake:

• Creamy Vanilla Lemon Curd Tart
• Orange Blossom Cupcakes
• Rhubarb Bars

Have you made these Blueberry Crumble Bars yet? Let me know how they turned out in the comments below—I’d love to hear about your triumphs! And if you snap a pic, tag me on Instagram @RiseAndBakeWithJulie.

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