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Blueberry Crumble Bars

This easy Blueberry Crumble Bars recipe features two layers of buttery, crispy baked oats sandwiching a juicy, jammy blueberry center that’s bright with fresh lemon. Perfect for grab & go breakfasts, snacking, or a simple summer dessert! 

A stack of four blueberry crumble bars.

Make the most of summer’s berry bounty with this easy recipe for Blueberry Crumble Bars! It features a buttery oats crumble that doubles as a pressed-in crust and a crispy crumb topping, plus a layer of sweet, jammy blueberries sandwiched in between. I squeezed some fresh lemon juice and zest into the berry layer, which makes this blueberry treat shine even brighter. Enjoy the blueberry bars for breakfast or brunch, or as a snack – or serve them as a simple summery dessert!

Why WE Love These Blueberry Crumble BarS

One of the biggest highlights of summer is the abundance of fresh, local fruits and vegetables. We go strawberry and blueberry picking almost every year, and have our own raspberry patch – these give us buckets of the best tasting berries you can imagine. So, of course, I have to bake with them! Here’s why my family loves this recipe:

  • Fresh & juicy-jammy. Summer’s best sweet-tart blueberries are truly the star of this blueberry crumb bar recipe. Even better if they’re recently picked!
  • Cozy. Around here, we adore buttery, crispy baked oats layers (like the topping on strawberry rhubarb crisp and my favorite apple crisp) – and this recipe features TWO of these layers. The bottom layer is pressed in, like an oat shortbread. And the top layer is in the form of crunchity crumbles. LOVE!!
  • So easy. This simple recipe calls for common ingredients and roughly 15 minutes of hands-on time.
  • Versatile. These bars are a great mid-morning or afternoon snack, a fun little breakfast on-the-go, or dessert.
Six blueberry crumble bars on a white background.

Recipe Ingredients

Here’s a look at the ingredients in these blueberry oatmeal crumble bars. Scroll down to the printable recipe card at the end of this post for the exact ingredient amounts.

The crumble ingredients are shown labelled: oats, flour, maple syrup, butter, brown sugar, baking powder, cinnamon.

For the Crumble Crust & Topping

  • Flour – All-purpose flour helps create the crumble mixture.
  • Oats – I use old-fashioned oats, which are larger and hold up better than quick cooking (instant) oats. They add texture and crunch to the crumble after it’s baked. 
  • Brown sugar – This adds rich, warm sweetness.
  • Baking powder – This ingredient allows the crumble to rise and take on more crispy texture.
  • Cinnamon – For a touch of warm spiced flavor.
  • Butter – This helps to hold the crumble mixture together, plus gives rich flavor.
  • Maple syrup – I love the natural sweetness and unique flavor that this adds to the crumble.
The ingredients for the blueberry layer is shown labelled: blueberries, lemon, sugar, cornstarch.

For the Blueberry Layer

  • Blueberries – I recommend using fresh berries, for the best flavor and texture. See my notes below about using frozen berries.
  • Sugar – Granulated sugar sweetens the blueberries and helps to create a sweet, jammy texture. 
  • Cornstarch – This ingredients thickens and binds together the blueberry layer so that it doesn’t seep into the crumble crust. 
  • Lemon juice & zest – Use freshly squeezed lemon juice for the best, freshest flavor. I also include some lemon zest, which helps to magnify that fresh lemon flavor.

Should I Use Fresh or Frozen Berries?

I recommend using fresh blueberries for this recipe because they provide the best blueberry flavor and texture. However, you can use frozen berries in a pinch. Just incorporate them from frozen; do not thaw them first.

Blueberry crumble bars surrounded by fresh lemons and bowls of blueberries.

How To Make Blueberry Crumble Bars

See my photos below to guide you through making these fruit bars. Find the detailed instructions in the recipe card lower down.

  • Prep. Preheat the oven. Line a 9″x13” pan with parchment paper, or just spray the pan well with nonstick baking spray.
  • Make crumble mixture. Mix the flour, oats, brown sugar, baking powder, and cinnamon, then stir in the melted butter and maple syrup.
  • Press into pan, then bake. Press two-thirds of the crumble mixture into the bottom of the pan, then bake it for 10 minutes.
  • Combine ingredients for blueberry layer. Mix the blueberries, sugar, cornstarch, lemon juice, and lemon zest.
  • Add blueberries to pan. Spread the blueberries evenly over the crust.
  • Add crumble. Sprinkle the remaining crumble mixture over the top of the blueberries.
  • Bake. Bake for 60-65 minutes. Let pan cool completely on a baking rack, then cut into bars.
A batch of blueberry crumble bars, the one in the middle has a bite taken out.

Tips & Variations

I love branching out on this base recipe and trying other types of fruit or adding nuts or other flavorful tidbits. Here are are few ideas to get you started:

  • Use the freshest blueberries. This should go without saying, but the freshest, sweetest blueberries will make this simple recipe spectacular.
  • Add nuts. For a little extra crunch, add sliced or chopped almonds, walnuts, or pecans to the crumble topping.
  • Other spices. In addition to, or instead of the cinnamon, you can try other ground spices. A little ground ginger or nutmeg is nice here, or just add more ground cinnamon.
  • Swap the maple syrup. If you don’t have maple syrup, substitute honey.
  • Sub in orange zest. Blueberry and orange is another great combination. For a slight flavor twist, sub in orange juice and zest for the lemon.

Serving Suggestions

Blueberry bars are a delicious choice morning, noon, or night!

Proper Storage

I’ve outlined below a few different options for storing these bars:

  • Counter – Place the bars in an airtight container and keep them on the counter for up to 2 days – just know that the crispy texture will soften with time. To retain some of that crispy crumble texture, store the bars uncovered.
  • Fridge – Keep blueberry crumble bars in an airtight container in the fridge for up to 5 days.
  • Freezer – Place blueberry bars in a freezer-safe container with parchment paper between layers, and store in the freezer for up to 3 months. Thaw bars in the fridge before serving.

More Blueberry Recipes To Try

A stack of four blueberry crumble bars.

Blueberry Crumble Bars

Yield: 12 bars
prep time: 15 minutes
cook time: 1 hour
total time: 1 hour 15 minutes
This easy Blueberry Crumble Bars recipe features two layers of buttery, crispy baked oats sandwiching a juicy, jammy blueberry center that's bright with fresh lemon. Perfect for grab & go breakfasts, snacking, or a simple summer dessert! 
5 Stars (1 Review)
Print

Ingredients

For the Crumble Crust & Topping

  • 2 cups all-purpose flour
  • 2 cups old fashioned oats
  • ½ cup brown sugar
  • ½ teaspoon baking powder
  • ¼ teaspoon cinnamon
  • 1 cup unsalted butter, melted
  • ¼ cup pure maple syrup

For the Blueberry Layer

  • 3 cups fresh blueberries
  • ¼ cup granulated sugar
  • 2 tablespoons cornstarch
  • 2 tablespoons freshly squeezed lemon juice
  • 1 teaspoon lemon zest

Instructions

For the Crumble Crust & Topping

  • Preheat oven to 350℉. Line a 9"x13” pan with parchment paper or spray it generously with nonstick cooking spray.
  • In a medium bowl, stir together flour, oats, brown sugar, baking powder, and cinnamon. Add melted butter and maple syrup, and stir until clumps of dough begin to form.
  • Press two thirds of the crumble mixture into the bottom of the pan and smooth it into an even layer. Set remaining crumble mixture aside. Bake crust for 10 minutes while you prepare the blueberry layer.

For the Blueberry Layer

  • In a medium blow, stir blueberries, sugar, cornstarch, lemon juice, and lemon zest until evenly combined.
  • Spread blueberry mixture evenly over the par-baked crumble crust.
  • Sprinkle the remaining crumble mixture over the top of the blueberries. Bake for 60-65 minutes, or until the crumble is golden brown and crisp.
  • Allow bars to cool completely in the pan. Then remove them from the pan using the parchment paper and cut into your desired size. You can also pop the bars in the fridge for an hour to make slicing even easier if needed.

Notes

Enjoy right away. Store any leftovers in an airtight container in the fridge for up to four days, or in an freezer-safe, airtight container for up to 3 months. 

Nutrition Information:

Serving: 1 Calories: 359kcal Carbohydrates: 50g Protein: 4g Fat: 17g Saturated Fat: 10g Polyunsaturated Fat: 1g Monounsaturated Fat: 4g Trans Fat: 1g Cholesterol: 41mg Sodium: 144mg Potassium: 134mg Fiber: 3g Sugar: 21g Vitamin A: 493IU Vitamin C: 5mg Calcium: 42mg Iron: 2mg
Nutrition information is automatically calculated by Spoonacular. I am not a nutritionist and cannot guarantee accuracy. If your health depends on nutrition information, please calculate again with your own favorite calculator.
Did you make this recipe?Please leave a comment below. And share a photo on Instagram with the hashtag #afarmgirlsdabbles or tag @farmgirlsdabble!

This post was first published in 2016, then updated in 2024.

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32 comments on “Blueberry Crumble Bars”

  1. Did you bake the bottom layer any before adding the blueberry filling? I tried these today, and the bottom layer didn’t end up like your photo. They were tasty, but mine didn’t look like yours and were less like bars than I expected. Thanks!

  2. amanda @ fake ginger

    Love that topping! I want a bar right now!

    Land O Lakes is definitely my go to butter. You can always count on consistency with them!

  3. Does the total butter content of this recipe really equal a whole pound or is my math not correct?
    Not judging, this recipe looks wonderful and I’m going to make it today. I am wondering if I can sub a stick or two of salted butter as I don’t have quite enough unsalted to make these bars.

    1. Your math is correct, Kathy, for this 9″ x 13″ pan of bars. Go ahead and sub some salted butter. Depending on how much salted butter you use and your liking for salt, you might want to reduce the addition of the salt in both the bottom layer and the crumble topping. I hope you like this! :) 

  4. Brian @ A Thought For Food

    See, I’d just be nibbling on these beautiful bars all day and night (they go great with come ice cream, right?)

  5. Cathy Beshore

    I can’t wait to try them.  My husband and I just went and picked more blueberries today (our fourth time), and I can picture them in this recipe!!  Thanks so much!!!

  6. Alaina @ A Not So Quiet Kitchen

    These oat crumble bars look so crazy good! I’m taking my kiddos blueberry picking in a few days and I think we definitely have to whip up a batch of these with our blueberry haul! Yum!

  7. Rahul @samosastreet.com

    What stunning photos, Brenda ! Your blueberry bar looks gorgeous and the flavors sound outstanding!

  8. Megan {Country Cleaver}

    Yup, pretty sure blueberries are definitely one of the best things about summer!! Beautiful!

  9. Lisa @ Wine & Glue

    They have blueberries . . . and they look like a coffee cake . . . so that means I can totally eat them for breakfast right??  They look amazing!

  10. Seriously, there is just nothing like oats, butter and a little sugar, all baked into something delicious!