These best blueberry crumb bars have a crunchy crust, plenty of gooey blueberry pie filling, and a buttery crumble topping! You can use fresh blueberries or frozen blueberries to make the blueberry mixture.
Blueberry Crumble Bars
It’s no secret that I absolutely love baking with blueberries! And these delicious blueberry crumb bars might just be my favorite blueberry recipe yet. The flavors and textures are simply out of this world. They’re essentially a blueberry pie/blueberry crisp hybrid.
Cut into squares and topped with ice cream, these are the ultimate crowd-pleasing dessert treat. And yes: serving them with ice cream is an absolute must! Are they delicious without it? Of course… but they’re a million times better when you top that crumb topping with a giant scoop of vanilla.
Ingredients for Blueberry Crumble Bars
- Butter: Be sure to use butter that’s been brought to room temperature. Butter that’s too cold won’t evenly incorporate into the mixture. I suggest unsalted butter, but in a pinch, salted will work. Simply omit the salt called for.
- Sugar: For the best flavor, granulated sugar and brown sugar are used. However, in a pinch, all granulated sugar will work fine. I don’t suggest using all brown sugar.
- All-Purpose Flour: I don’t suggest using any flour substitutes! But if you’re going to experiment, your best bet is a 1-for-1 GF flour. Nut flours will not work in this recipe.
- Salt: A small amount of salt both cuts the sweetness and helps enhance all of the other flavors in this recipe. Fine sea salt works great, but regular table salt will also work fine.
- Egg: Be sure to use a large egg and bring it to room temperature before adding it to the batter.
- Sour Cream:
- Lemon: You’ll use both the lemon juice and the lemon zest in this recipe. Surprisingly, the bars do not have an intense lemon flavor. Instead, it enhances the blueberry flavor and it gives it a pop of freshness.
- Cornstarch: In addition to flour, cornstarch helps thicken the custard filling.
- Cinnamon: A tiny dash enhances the blueberry flavor and adds a subtle warmth. You may skip this or use a dash of nutmeg instead.
- Vanilla Extract: Vanilla adds sweetness and enhances all of the other flavors in the recipe. Always use pure vanilla extract, and not artificial vanilla.
- Blueberries: Fresh or frozen blueberries work fine in this recipe. If you’re using frozen blueberries, DO NOT thaw them first.
No leavening agents are used in this recipe (baking soda/baking powder). So the blueberry bars bake up dense, buttery, and intensely fruity!
How to Make Them
- Baking Prep: Preheat the oven and line an 8×8-inch baking pan with parchment paper. Spray the pan with non-stick baking spray and set the prepared pan aside until needed.
- Make the Crust/Crumb Topping: The crust and crumb topping are one recipe that gets divided. You’ll reserve 1 cup for the crumb topping, and press the rest into the bottom of the prepared pan.
- Make the Blueberry Filling: In a mixing bowl, combine the egg, sour cream, sugar, cornstarch, lemon, flour, cinnamon, and vanilla. Fold in 1 and 1/2 cups of the blueberries.
- Assemble the Bars: Pour the filling over the crust, then sprinkle the remaining blueberries on top. Use your hands to scatter the remaining crust over the filling.
- Bake the Bars: You’ll need to bake for about 1 hour. And then let the bars cool completely in the pan (about another hour) before serving them. Waiting for them to cool and firm up is definitely the hardest part of this recipe!
- Slice and Serve: Use the parchment paper to help you remove the bars from the pan. Cut into squares and serve with ice cream!
You can wrap any leftovers in Saran Wrap and store in the fridge for up to 3 days!
Tools for this Recipe
- 8×8-Inch Baking Pan
- Parchment Paper
- Nonstick Baking Spray
- Mixing Bowl
- Electric Hand Mixer
- Large Knife
More Crumb Bars:
Blueberry Crumb Bars
Ingredients
For the Crust/Crumb Topping:
- 3//4 cup (170g) unsalted butter room temperature
- 3/4 cup (149g) granulated sugar
- 1/4 cup (53g) light brown sugar packed
- 2 cups (240g) all-purpose flour
- 1/4 teaspoon salt
For the Blueberry Filling:
- 1 large egg room temperature
- 2/3 cup (151g) full-fat sour cream
- 1/2 cup (106g) light brown sugar packed
- 1/4 cup (50g) granulated sugar
- 2 Tablespoons (28ml) lemon juice freshly squeezed
- 2 Tablespoons (28g) all-purpose flour
- 1 Tablespoon (10g) cornstarch
- 1/2 teaspoon ground cinnamon
- 2 teaspoons vanilla extract
- 2 teaspoons lemon zest finely grated
- 2 and 1/2 cups (375g) blueberries fresh or frozen, divided
- ice cream for serving, optional
Instructions
For the Crust/Crumb Topping:
- Preheat the oven to 350 degrees (F). Line an 8×8-inch baking pan with parchment paper, allowing paper to overhang on two of the ends. Spray with non-stick baking spray and set aside.
- In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a handheld electric mixer, beat together the butter and sugars until light and fluffy, about 2-3 minutes.Â
- On low speed, add flour and salt, and mix until combined. The dough will be crumbly.Â
- Remove 1 cup and reserve for later use. Press the remaining crust mixture evenly into the bottom of the prepared baking pan. Bake for 10 minutes.Â
- Remove from the oven and set on a cooling rack to cool as you prepare the filling. Keep oven temperature at 350.Â
For the Blueberry Filling:
- In a large bowl, whisk together the egg, sour cream, both sugars, lemon juice, flour, cornstarch, cinnamon, vanilla, and lemon zest until smooth and well combined, about 2 minutes. Using a rubber spatula, gently fold in 1 and 1/2 cups (275g) of the blueberries.
- Pour the filling mixture over the crust, shaking the pan gently, then evenly sprinkle the remaining (100g) blueberries on top.Â
- Take the reserved crust and scatter it over the top of the berries, squeezing the mixture in your hands to encourage large lumps.
- Bake for 1 hour. Let cool for at least 1 hour before removing the bars from the pan. When ready to serve, cut into squares and serve with ice cream. Â
Karla says
I just made these today. They are AMAZING! I didn’t change anything, except using frozen blueberries instead of fresh. They are not too sweet, which I love. The blueberry flavor shines thru. The ginger and lemon are the perfect touch to bring it all together. Definitely a keeper. Thank you so much for sharing this wonderful recipe.
bakerbynature says
Hi Karla. So happy to hear it! We love those bars too 🙂 Happy Thanksgiving!
Jenn Foulds says
Will this recipe work with frozen wild blueberries?
bakerbynature says
Yes! Just be sure they are frozen (defrosted frozen berries will smash too easily).
Tieghan Gerard says
Love blueberries and of course the crumbs! Mmm!
bakerbynature says
Thank you, T!
amanda @ fake ginger says
Oh man, I love anything with crumb topping! I need these!
bakerbynature says
Crumb topping is the beeeeest 🙂 xo
Caroline says
These look ahhhhh-mazing!!
bakerbynature says
Thanks, girlie!!! xo
Claire Gallam says
This looks to die for!
bakerbynature says
Thank you, friend! xo
Millie l Add A Little says
These are bursting with blueberries and look amazing! Love the sound of crystallised ginger to give it warmth and a bit of a kick!
http://youtube.com/addalittlefood
bakerbynature says
The ginger is soooooo good 🙂
Baby June says
Those look delicious! I love blueberry cobbler, I’m sure it tastes even better in bar form. 🙂
Liz @ The Lemon Bowl says
These look so good I can’t take it!
bakerbynature says
If you can’t take it… ya gotta make it 😉 xo
Marcie says
Now this is a blueberry dessert! I love that beautiful, thick layer of fruit! Pinning.