Wild Blueberry Crumble Bars
These blueberry crumble bars are made bakery-style by baking them super thin and slicing into giant squares. Each bite has the perfect ratio of buttery crumble to sweet and jammy blueberry filling. Plus, the filling is made with frozen wild blueberries so not only is this recipe quick and easy, but the filling is seamless with no large chunks!
Blueberry Bars Recipe Inspiration
The inspiration from this recipe came straight from some bars I saw while grocery shopping at Whole Foods. Their bakery section has these lemon blueberry bars that are large and thin and just look so delicious. It reignited my love for thin layers sliced into large squares. Something about it just looks so much more appealing. So be prepared for more thin bars around here because it’s all I can think about!
Why Make Wild Blueberry Bars?
I have frozen wild blueberries in my yogurt every morning so I always have a big bag on hand. When developing this recipe, I decided to just use what was already in my kitchen! Plus, I love the flavor of wild blueberries. They’re sweeter and stronger than typical fresh blueberries.
Using wild blueberries also makes the filling incredibly quick and simple. Just scoop 3 cups into a saucepan. No cleaning or picking through needed! And when heating, no mashing is involved either. The berries are so tiny that they don’t need to be broken up.
The end result is an incredibly thin but flavorful layer that bakes beautifully in these blueberry bars.
Blueberry Crumble Tips
Once the filling is made, it chills in the refrigerator while we make the crumble. It’s incredibly quick, but there are a few things to keep in mind to ensure it doesn’t turn out too tough and dry.
- Flour – If possible, weigh the flour with a food scale. If not, spoon it into your measuring cup and level it off for light and fluffy cups. Scooping directly into the flour packs it down into the cup, thus leading to too much flour and a dry crumble.
- Mixing – Toss the dry ingredients together with your hands and break up an potential brown sugar lumps along the way.
- Butter – Use melted butter that’s not TOO hot. It can be slightly warm, but definitely not steaming. Butter that’s too hot will make the crumble stickier than usual, thus harder to handle.
- Assembly – Press about 2/3 of the crumble into the pan or enough to cover in a thin layer. The layer might feel alarmingly thin, but that’s what we want!
- Top – Break up the crumble into tiny pieces as you sprinkle over the filling. Cover as much of the filling as possible, so you can nudge the crumble around the surface if needed.
Wild Blueberry Crumble Bars FAQ
You can, the filling just won’t be as juicy!
You can, but keep in mind that you will have seeds (like for raspberries or blackberries) so as long as that doesn’t bother you, then go for it. Also make sure the filling reaches a thickened consistency on the stove top as some berries contain more water than others.
Absolutely! Just swap in a 1 to 1 gluten free baking flour. I like Bob’s Red Mill (the blue bag) or King Arthur.
Unfortunately it doesn’t make quite enough to fill an 8×8 pan.
Once cooled and sliced, store in a container or ziplock bag in the refrigerator and they’ll keep for about 5 days. They can be left at room temperature for about a day as well, but they will soften over time.
For more berry dessert recipes, check out my:
- Strawberry Pizza
- Fruity Cheese Danish
- Strawberry Rhubarb Crisp
- Blueberry Cream Cheese Cobbler
- BEST Blueberry Muffins
- Fresh Strawberry Sheet Cake
- Roasted Strawberry Cheesecake
Or try my Brown Sugar Berry Crumble Bars!
Make sure to tag me @butternutbakery on Instagram and leave a review below if you make these blueberry crumble bars. To pin this recipe and save it for later, you can use the button on the recipe card, the buttons above or below this post, or on any of the photos above. Happy baking!
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Wild Blueberry Crumble Bars
- Total Time: 2 hours 25 minutes
- Yield: 12 or 24 Bars
Description
These wild blueberry crumble bars have perfectly thin layers of buttery crumble and jammy lemon blueberry filling! They’re so quick and easy to make using frozen berries and melted butter. Plus, since they’re so thin, they cool quickly so they’re ready to slice in under 2 hours!
Ingredients
Wild Blueberry Filling
- 1 lemon
- 3 cups (375g) frozen wild blueberries
- 3 tbsp granulated sugar
- 1 tbsp cornstarch
- 1 tsp vanilla extract
Crumble
- 1/2 cup (100g) light brown sugar, packed
- 1/2 cup (100g) granulated sugar
- 2 3/4 cups (354g) all-purpose flour or 1-to-1 gluten-free baking flour, spooned and leveled
- 1/2 tsp kosher salt
- 1 tsp baking powder
- 1 cup (224g) unsalted butter, melted and cooled
Instructions
Wild Blueberry Filling
- First, zest the lemon and set aside the zest.
- In a medium saucepan combine the blueberries first with the sugar and cornstarch, and then juice of the lemon. Stir to coat. Place over medium heat and stir occasionally with a wooden spoon or rubber spatula.
- After about 5 to 8 minutes, the mixture will start to steam and bubble. Stir continuously for another 5 minutes or until the mixture is thickened and glossy, like pie filling.
- Remove from heat and mix in the lemon zest and vanilla. Pour into a wide and shallow dish and allow to cool in the refrigerator while we make the crumble.
Crumble
- Preheat the oven to 350F and grease the inside of a 9×13 baking dish. Line the bottom and all sides with parchment paper.
- Add the brown sugar, sugar, flour, salt and baking powder to a large bowl. Use your hands to mix and toss together, breaking up any brown sugar lumps as you go.
- Use a rubber spatula to stir in the butter. Spend a good couple minutes on this to ensure the mixture is evenly hydrated and no dry patches remain. It should look moist but very crumbly.
- Scoop about ⅔ of the crumble into the pan and press into a thin and even layer all the way to the edges.
- Spread the blueberry filling on top, also in a thin and even layer. Then sprinkle the remaining crumble on top, taking care to ensure the blueberry is evenly covered.
- Bake for 35 to 40 minutes or until lightly golden on top.
- Allow to cool at room temperature for about 15 minutes, then transfer to the refrigerator to cool completely, about 45 minutes.
- Then remove from the pan and slice into 12 large bars or 24 regular bars. Enjoy!
Equipment
Buy Now → - Prep Time: 20 minutes
- Cooling Time: 90 minutes
- Cook Time: 35 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
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Meet Jenna
I’m the creator, baker, and photographer behind Butternut Bakery. Here I share desserts for every diet because I believe everyone should have a chance to indulge!
