Blueberry Crumble Bars
These Blueberry Crumble Bars feature a juicy blueberry filling layered between buttery oatmeal crumble for an easy dessert that tastes like blueberry crisp in bar form. Made with fresh or frozen blueberries, they’re perfect for summer gatherings, picnics, potlucks or anytime you need a simple fruit dessert!
If you love easy blueberry desserts, these Blueberry Crumble Bars deserve a spot on your summer baking list. They’re simple to make with pantry staples, fresh or frozen blueberries, and a buttery oat crumble that doubles as both the crust and topping for the perfect mix of soft, jammy fruit and crisp texture.
Unlike cobblers or crisps, crumble bars are sturdy enough to slice and travel well, making them perfect for BBQs, picnics, potlucks or make-ahead desserts. They’re also easy to customize — use coconut sugar for deeper caramel flavor, swap in brown sugar or granulated sugar, or make them gluten-free or dairy-free with simple substitutions.
Wondering how to prevent soggy crumble bars, use frozen blueberries, or get clean slices? I’ve included my best tips below. 🙂
Why you’ll love this recipe
- These blueberry crumble bars include a sweet, juicy blueberry filling with fresh lemon juice and zest paired with a hearty buttery oat crumble.
- The bars are everything you love about fruit crisp in a portable dessert that’s perfect for picnics, BBQs, potlucks and summer gatherings.
- They’re great for making ahead because the bars slice best once cooled and fully set.
- They can be made gluten-free and dairy-free with just 2 simple swaps.
Recipe ingredients
These blueberry crisp bars are made with simple pantry staples plus juicy blueberries and lemon for bright fresh flavor.
- Old fashioned rolled oats. Use old fashioned rolled oats for a nice chewy texture. Quick oats may be used in a pinch.
- Flour. Substitute the all purpose flour with whole wheat flour or spelt flour for added fiber, or gluten-free 1 to 1 flour or oat flour to make this recipe gluten-free.
- Coconut sugar. Coconut sugar adds a deeper caramel-like flavor without being overly sweet. If you prefer not to use it, I recommend using packed light brown sugar for the crumble and granulated sugar or maple sugar in the blueberry filling.
- Cinnamon. Adds warm, cozy flavor to the oat crumble.
- Butter. Swap the butter with melted coconut oil to make this recipe dairy-free.
- Blueberries. Fresh blueberries work best for the juiciest filling, but frozen blueberries may also be used. If using frozen berries, thaw slightly and blot excess moisture with paper towels to prevent the bars from becoming watery.
- Lemon zest and juice. Lemon brightens the blueberry flavor and balances the sweetness without making the bars taste lemony.
- Cornstarch. You’ll need 2 tablespoons of cornstarch to thicken the filling and make the bars nice and slice-able.
See the recipe card below for the full list of ingredients and quantities.
How to make this recipe
These blueberry crumble bars couldn’t be easier to make. The oat crumble comes together in minutes, there’s no fruit to chop, and the bars bake into a golden, jammy dessert that tastes even better after cooling.
Pro tip: Cool the bars completely before slicing. The blueberry filling sets as it cools, which ensures clean slices that hold together.
See the recipe card below for full instructions.
Tips for success
- Line the pan with parchment paper for easy removal and cleaner slices.
- Cool completely before cutting to prevent messy bars.
- Use rolled oats for best texture. Quick oats soften more and won’t create the same hearty crumble.
- If the crumble browns too quickly, loosely tent with foil during the final 15-20 minutes.
- For extra crisp crumble, refrigerate the crumble mixture for 10 minutes before baking.
Recipe FAQs
Yes! Frozen blueberries work well in this recipe. Thaw slightly and blot dry with paper towels to remove excess moisture before mixing with the filling ingredients.
Yes. Substitute the all purpose flour with oat flour or your favorite gluten-free 1:1 flour blend.
Serving suggestions
The bars are delicious as is, or you can serve them with a scoop of vanilla ice cream or homemade whipped cream. Use my coconut whipped cream recipe for a dairy-free option.
Storage and make ahead tips
- Store leftover blueberry crumble bars covered at room temperature for up to 3 days or refrigerate for up to 1 week.
- These bars are also freezer-friendly. Wrap individual bars tightly and freeze for up to 3 months. Thaw overnight in the refrigerator or at room temperature before serving.
- Because the bars slice best after cooling, they’re a great make-ahead dessert for parties, BBQs or meal prep.
More summer desserts you’ll love:
Did you try this recipe? If so, be sure to leave a review below and tag me @flavorthemoments on Facebook and Instagram
Blueberry Crumble Bars
Ingredients
For the oatmeal crumble:
- 1 1/2 cups all purpose flour sub with oat flour for gluten-free option
- 1 1/2 cups old fashioned rolled oats
- 1/3 cup coconut sugar sub with packed light brown sugar
- 1 teaspoon ground cinnamon
- 1/4 teaspoon sea salt
- 3/4 cup unsalted butter melted; sub with coconut oil for dairy-free option
For the filling:
- 3 cups blueberries about 1 1/2 pints
- 1/2 cup coconut sugar
- 1 tablespoon lemon zest
- 1 tablespoon fresh lemon juice
- 2 tablespoons cornstarch
Instructions
- Preheat the oven to 375 degrees. Line an 8×8" baking dish with parchment paper or foil. Place the flour, oats, 1/3 cup sugar, cinnamon and salt in a medium bowl and stir well to combine. Add the melted butter, stirring until the dry ingredients are moistened. When you pinch the crumble together, it should hold together.1 1/2 cups all purpose flour, 1 1/2 cups old fashioned rolled oats, 1/3 cup coconut sugar, 1 teaspoon ground cinnamon, 1/4 teaspoon sea salt, 3/4 cup unsalted butter
- Press 2/3 of the oat crumble into the bottom of the prepared pan and bake for 8-10 minutes until golden.
- Place the blueberries, 1/2 cup sugar, lemon zest and juice, and cornstarch in a medium bowl and stir until combined. Pour the blueberry mixture evenly over the crumble, then sprinkle the remaining 1/3 of the crumble over the blueberry mixture.3 cups blueberries, 1/2 cup coconut sugar, 1 tablespoon lemon zest, 1 tablespoon fresh lemon juice, 2 tablespoons cornstarch
- Bake for 35-45 minutes until the center is bubbly, covering with foil after 30 minutes if the crumble is browning too quickly. Cool the blueberry crumble bars completely on a wire rack for a minimum of 3 hours or overnight until set. Cut into bars and enjoy!
Video
Notes
- Pro tip: Cool the bars completely before slicing. The blueberry filling sets as it cools, which ensures clean slices that hold together.
- Fresh or frozen blueberries work well in this recipe. If using frozen blueberries, thaw slightly and blot dry with paper towels.
- Store leftovers at room temperature for up to 2 days or in the refrigerator for up to 1 week.
Nutrition
Nutrition is estimated using a food database and is only intended to be used as a guideline for informational purposes.
8 Comments on “Blueberry Crumble Bars”
You know I love a good crumble bar Marcie, and blueberries are so easy to work with. No chopping required! Need to try these when local blueberries are in season here later this summer!
Yes I do! 🙂 Thanks Leanne!
We love blueberries around here, so when they’re on sale in the summer, we always stock up!! These crumble bars look fantastic!! A perfect summer bar 🙂
I stock up in the summer too! Thanks Katherine!
Aww, great minds are thinking alike, Marcie! I was working on some crumble bars over the weekend. I used quince jam for mine though 🙂 These look so lovely, and I am a huge blueberry fan! Great to know I can use frozen blueberries as it is Winter here at the moment! 🙂
‘Tis the season for crumble bars right? And quince jam sounds like an amazing filling!
Could I use frozen blueberries and do I need to drain them after thawing?
Yes! Frozen blueberries will work fine, simply thaw them and blot them dry before using. If they’re not super sweet, you may want to add a bit more sugar if you like a sweeter dessert.