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7-Ingredient Blueberry Oatmeal Crumb Bars (Gluten-Free, Vegan)

Blueberry Oatmeal Crumb Bars are the loveliest treat! Enjoy them for dessert, an afternoon snack, or even breakfast! Your friends and family will go bonkers over these delicious blueberry pie bars!

Blueberry crumb bars cut on a piece of parchment paper.

Blueberry dessert lovers, this just in!

Just like my Raspberry Crumb Bars, Vegan Blackberry Pie Bars, and my Strawberry Oatmeal Bars, these Blueberry Oatmeal Crumb Bars feature a delightful fresh fruit filling on top of an amazing buttery shortbread-like layer with a tasty crumble topping. 

Made using wholesome ingredients you probably already have on hand, these yummy bars have a rustic little vibe about them.

Plus, they are gluten-free, can easily be made refined sugar-free, and are vegan. A major win for those who have dietary restrictions for various reasons. 

The best part about these fun crumble bars is they are easy to make. You don’t need to be a seasoned baker to find great success with this simple recipe!

There’s no cutting cold butter into flour using a pastry cutter, no need to chill the pastry crust dough in the refrigerator, and no fancy equipment needed.

Whenever I make these bars and present them to my friends and family, they disappear in a nanosecond. 

Truly, the people love their fruity desserts!

Blueberry crumb bar on a wooden plate with a golden fork and blueberries

For a grain-free version of this recipe that uses almond flour, make my Paleo Blueberry Crumb Bars. For a low carb version, make my Low-Carb Blueberry Crumb Bars

Let’s discuss the simple ingredients for blueberry crumb bars.

Ingredients for Blueberry Oatmeal Crumb Bars:

Fresh Blueberries: The star of the bars, we use juicy blueberries to make a perfectly sweet gooey berry jammy filling. Any fresh berries will work here.

Frozen blueberries will work too but for the best results, use fresh blueberries.

Lemon Juice: If your blueberries aren’t very tangy, add a couple tablespoons of lemon juice to the blueberry filling. This will help bring out more of a classic berry flavor.

The hint of lemon will actually bring out the blueberry flavor. If you’d like to get fancy, you can add lemon zest to the crumble base.

Sweetener of Choice: Choose your favorite sweetener for baking. You can use granulated sugar, brown sugar, pure maple syrup, coconut sugar, or sugar-free sweetener.

Gluten-Free All-Purpose Flour: Choose your favorite brand of gluten-free all-purpose flour to use as the base and topping of these delicious blueberry bars.

I use either Bob’s Red Mill Gluten-Free 1-to-1 Baking Flour (my personal favorite GF blend), King Arthur Measure for Measure, or Pamela’s Artisan Gluten-Free Flour

Any brand of gluten-free flour will work as long as it is meant to be  a 1:1 replacement for regular all-purpose flour. In this sense, paleo flour blends or keto flour blends won’t always work.

A little flour is also added to the blueberry mixture to help thicken it up. Without the flour, the blueberry layer will be too runny but we want it to be nice and jammy.

Gluten-Free Rolled Oats: Adding oats to the flour mixture gives it that warm and inviting nutty flavor that we all love so much in oatmeal treats. Use old fashioned rolled oats or quick oats.

I use sprouted gluten-free oats. To make this recipe gluten-free, be sure your oats are certified gluten-free (the package will say so).

Coconut Oil or Unsalted Butter: The fat portion of the recipe that brings all the shortbread base ingredients together in a delicious dough. You can use either melted butter or melted coconut oil.

To make vegan blueberry crumb bars, use melted coconut oil. The great news is we don’t need a pastry cutter to cut in chilled butter – we keep it easy by using melted!

Vanilla Extract: If you have it on hand, pure vanilla extract adds lovely warmth to the buttery crust. Skip it if you don’t have it on hand.

Sea Salt: Be sure to add a pinch of sea salt to both the blueberry filling and the crust and topping mixture. This will enhance all of the flavors and make the bars taste richer.

Optional Glaze:

Powdered sugar and water (or lemon juice) makes a delightful glaze for the blueberry bars. If you’re looking to keep the bars sugar-free to control blood sugar, use a sugar-free confectioner’s sweetener.

Now that we’re familiar with the blueberry crumb bar ingredients, let’s bake them!

Drizzling powder sugar glaze on top of blueberry crumb bars.

How to Make Blueberry Oatmeal Crumb Bars:

Preheat the oven to 350 degrees Fahrenheit and line an 8” x 8” cake pan or 9” x 9” square pan with parchment paper

Add all of the ingredients for the shortbread crust and topping to a large mixing bowl and mix until a thick dough forms. There’s no need to separate the dry ingredients from the wet ingredients here. 

Ingredients for crust and crumb topping in a mixing bowl, ready to be mixed together

It’s perfectly normal for this mixture to be slightly crumbly but if it seems overly dry (in other words, it won’t mix), you can add more melted oil or butter until it resembles a slightly drier version of regular cookie dough.

Note: You can also use a food processor for this step as well.

Measure out ¾ cup of the crumble mixture and set it aside to use later as the crumb topping.

Crust pressed into a baking pan with some reserved crumble topping to the side

Transfer the remaining crust mixture to the bottom of the prepared pan and press it into an even layer. Poke the crust several times with a fork (to promote even baking) and bake for 15 to 18 minutes, or until the edges are just barely beginning to turn golden brown.

While the crust is baking, you can prepare the blueberry mixture.

Transfer all of the ingredients for the blueberry filling to a saucepan (fresh blueberries, lemon juice, gluten-free all-purpose flour, sweetener and salt).

Stir well, cover, and heat over medium-high heat. The berries will begin to bubble and leach liquid after a few minutes.

At this point, you can use a fork or a potato masher to mash the berries to allow the juices to flow. Continue heating just until the berry mixture is thick yet still liquidy, about 3 to 5 minutes.

blueberries, flour, and sugar in a saucepan to make blueberry filling.

Once the crust is out of the oven, pour the blueberry mixture on top of the crust and spread it into an even layer.

blueberry layer on top of shortbread crust layer to make blueberry bars.

Sprinkle the reserved remaining crumble mixture over the blueberry layer.

Blueberry crumb bars, ready to go into the oven to bake.

Place the baking dish back into the oven and bake for another 22 to 30 minutes, or until the blueberry filling is bubbly and the topping is slightly golden brown.

Remove the blueberry bars from the oven and allow them to cool for 15 minutes before transferring them to the refrigerator to cool completely.

Blueberry crumb bar on a wooden plate with a bowl of blueberries and a napkin and fork around.

Once the bars have cooled, pull up on the parchment paper to transfer them to a large cutting board.

Use a sharp knife to cut individual bars.

If you’d like to make the optional glaze, combine the powdered sugar and water (or lemon juice) in a small bowl and stir until a thick runny glaze forms.

Drizzle the bars with glaze, serve, and enjoy!

For an even more decadent dessert, serve the bars with a scoop of my Dairy-Free Vanilla Ice Cream or my 3-Ingredient No-Churn Vanilla Ice Cream

Store bars in an airtight container in the refrigerator for up to 1 week. You can freeze the bars in a freezer bag or large zip lock bag in the freezer for up to 3 months.

Wooden plate with a blueberry crumb bar on top. Gold fork and napkin to the side.

And that’s it! An easy dessert recipe that is worthy of putting on constant rotation!

These easy bars are one of the best desserts for blueberry season, when there is an abundance of fresh fruit available at the grocery store.

A great recipe for special occasions or everyday living!

If you love dessert bar recipes like this, also try out these reader favorites.

More Healthy Desserts:

Blueberry crumble bars for breakfast!

Blueberry crumb bars cut on a piece of parchment paper.
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4.37 from 49 votes

Blueberry Oatmeal Crumb Bars

Sweet blueberry filling on top of buttery shortbread crust with a delightful crumb topping and delectible glaze. These easy blueberry crumb bars are the perfect dessert or even breakfast!
Prep Time15 minutes
Cook Time40 minutes
Total Time55 minutes
Course: Desserts & Treats
Cuisine: American
Servings: 12 bars
Calories: 303kcal
Author: Julia

Ingredients

For the Blueberry Filling:

  • 4 cups 18 ounces fresh blueberries
  • 2 Tbsp fresh lemon juice*
  • 2 Tbsp granulated sugar or pure maple syrup
  • 2 Tbsp gluten-free all-purpose flour
  • Pinch sea salt

Shortbread Crust and Topping:

Optional Glaze:

  • 1 cup powdered sugar
  • 2 Tbsp water or lemon juice

Instructions

  • Preheat the oven to 350 degrees Fahrenheit and line an 8” x 8” or 9” x 9” square pan with parchment paper. 
  • Add all of the ingredients for the shortbread crust and topping to a large mixing bowl and mix until a thick dough forms. There's no need to separate the dry ingredients from the wet ingredients here. 
  • It’s perfectly normal for this mixture to be slightly crumbly but if it seems overly dry (in other words, it won’t mix), you can add more melted oil or butter until it resembles a slightly drier version of regular cookie dough. Note: You can also use a food processor for this step as well.
  • Measure out ¾ cup of the crumble mixture and set it aside to use later as the crumb topping.
  • Transfer the remaining crust mixture to the bottom of the prepared pan and press it into an even layer. Poke the crust several times with a fork (to promote even baking) and bake for 15 to 18 minutes, or until the edges are just barely beginning to turn golden brown.
  • While the crust is baking, you can prepare the blueberry mixture.
  • Transfer all of the ingredients for the blueberry filling to a saucepan (fresh blueberries, lemon juice, gluten-free all-purpose flour, sweetener and salt). Stir well, cover, and heat over medium-high heat. The berries will begin to bubble and leach liquid after a few minutes. Use a fork or a potato masher to mash the berries to allow the juices to flow. Continue heating just until the berry mixture is thick yet still liquidy, about 3 to 5 minutes.
  • Once the crust is out of the oven, pour the blueberry mixture on top of the crust and spread it into an even layer.
  • Sprinkle the reserved remaining crumble mixture over the blueberry layer.
  • Place the baking dish back into the oven and bake for another 22 to 30 minutes, or until the blueberry filling is bubbly and the topping is slightly golden brown.
  • Remove the blueberry bars from the oven and allow them to cool for 15 minutes before transferring them to the refrigerator to cool completely.
  • Once the bars have cooled, pull up on the parchment paper to transfer them to a large cutting board.
  • Use a sharp knife to cut individual bars.
  • If you’d like to make the optional glaze, combine the powdered sugar and water (or lemon juice) in a small bowl and stir until a thick runny glaze forms.
  • Drizzle the bars with glaze, serve, and enjoy!
  • For an even more decadent dessert, serve the bars with a scoop of vanilla ice cream.

Video

Notes

*If the blueberries you’re using are already tangy, you can skip the lemon juice. For blueberries that are sweet and don’t have very much flavor, the lemon juice will help level up the flavor.
**If using pure maple syrup to sweeten the crust, add an additional 3 tablespoons of gluten-free all-purpose flour.
***If you’re using butter instead of coconut oil, use 2 sticks (1 cup) of butter (melted).
Store bars in an airtight container in the refrigerator for up to 1 week. You can freeze the bars in a freezer bag or large zip lock bag in the freezer for up to 3 months.
Nutrition Facts do not include the optional glaze.

Nutrition

Serving: 1Bar (of 12) | Calories: 303kcal | Carbohydrates: 42g | Protein: 3g | Fat: 15g | Saturated Fat: 11g | Polyunsaturated Fat: 1g | Sodium: 101mg | Fiber: 3g | Sugar: 16g

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Recipe Rating




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Gena

Wednesday 23rd of August 2023

Love these, but I don’t have any berries, so I am trying doctored up blueberry pie filling and am adding some toasted chopped pecans to the shortbread. Fingers crossed, I have been craving them and am unable to drive at the moment so just improvising. Wish me luck!

Julia

Friday 25th of August 2023

Love that! Good luck! Based on what you described, I imagine the bars should still turn out nicely. I hope you're enjoying them! xo

Brittany

Monday 14th of August 2023

Can I use frozen berries here? Would I need to make any adjustments?

Brittany

Monday 14th of August 2023

Can I use frozen berries for this? Any modifications I should make if I do?

Julia

Monday 14th of August 2023

Hi Brittany! Frozen berries should work. I would add a little water (I'd start with 3 to 4 tablespoons and add more if the mixture looks too dry) to the saucepan with the berries to help them heat up. Hope you enjoy the bars!

Susan

Wednesday 12th of July 2023

I made this for my husband who is gluten intolerant. He loves it! I used a 9x9 pan and I’m thinking next time I’ll use a few more blueberries and put a little bit less of the oat mixture on the bottom and a little more as crumble.

Question: did you sift the flour as you were measuring it or just spoon it lightly into the measuring cup?

Julia

Thursday 20th of July 2023

Hi Susan! I scooped the flour into the measuring cup using the measuring cup itself :) In my previous crumb bar recipes, I used half the amount of crust (and topping) but increased the amount to make the bars more substantial. If you like less crust, I would halve the crust recipe and use an 8" x 8" pan :) Hope this helps! xo

Cassie

Thursday 6th of July 2023

Can I use regular flour and oats without alteration of taste?

Julia

Monday 10th of July 2023

Hi Cassie! You should be able to use regular all-purpose flour and oats without having to make any other changes :) If you notice the crust mixture is very dry, you can always add more oil (or melted butter) until it resembles a regular crumb topping. Enjoy!

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