Blueberry Oatmeal Bars — 🫐💙 These EASY blueberry bars are buttery and packed with blueberry flavor! They have a perfect chewy meets crispy texture from the oatmeal crust and crumble topping with soft berry filling in the middle! They take just 10 minutes of prep and then go straight into the oven. So quick to make and a crowd pleaser every time! Either fresh or frozen berries are fine.
Table of Contents
This blueberry crumble bars recipe is an easy, one bowl, no mixer recipe that takes just minutes to make. I adapted the recipe from my Blueberry Pie Bars by reducing some of the flour and adding oats to the crust and crumble mixture. The oats add such great texture.
The crust and oatmeal crumble topping are one and the same. Love it when that happens so there’s one less step and one less bowl to wash!
The blueberry oatmeal bars aren’t overly sweet and the blueberry flavor shines beautifully, which is why they’re great for breakfast, brunch, snacks, or a healthy dessert. They’re soft and tender, yet slightly chewy from the oats, and I’m a sucker for anything with a crumble topping.
Ingredients for Blueberry Oatmeal Bars
To make the oatmeal blueberry bars, you’ll need:
- Unsalted butter
- All-purpose flour
- Old-fashioned oats
- Granulated and brown sugar
- Salt
- Blueberries
- Lemon juice
- Cornstarch
Note: Scroll down to the recipe card section of the post for the ingredients with amounts included and for more complete directions.
How to Make Blueberry Oatmeal Bars
This blueberry crumb bars recipe has been a reader favorite for years, both because the bars are delicious and because the prep work is so simple!
- Make the crust / topping mixture: Melt the butter in a large bowl before adding in some flour, oats, two types of sugar, and salt. Stir all of that together.
- Set some of the mixture aside to be sprinkled on later as the oatmeal crumble topping, then transfer the rest to a greased 8×8-inch baking pan.
- Make the blueberry filling: In the same bowl you made the topping in, add some blueberries, cornstarch, lemon juice, and sugar. Spread the blueberry filling over the crust.
- Sprinkle the reserved crumble topping over the blueberry layer before popping the blueberry bars into the oven.
- Bake: The edges should be just set and the oatmeal crumble topping will be golden.
Want to Make Lemon Blueberry Crumble Bars?
To make blueberry bars with a hint of lemon flavor in the filling, add the zest of a lemon to the filling. Don’t add extra lemon juice, as that would make the filling too runny.
Baking FAQs
I used frozen blueberries for these blueberry crumble bars, but I’m sure fresh would work as well. If you’re using fresh blueberries for these bars, I recommend reducing the bake time by 10 to 15 minutes (I haven’t made this recipe with fresh berries, so I can’t say for certain). When evaluating the doneness of your bars, it’s more important to decide based on how the bars look rather than how much time has passed.
Don’t use quick cook or instant oats because they’re finer than old-fashioned oats and behave like flour. Instant oats will make mixture too dry.
Yes, of course! I’ve also made Strawberry Bars, Mango Bars, and Cranberry Bars using this same base recipe.
Yes! I made this recipe for blueberry oat bars in a 8×8-inch pan, but you should be fine to double the recipe and bake the blueberry crumble bars in a 9×13-inch dish.
I haven’t ever tried any of those flour alternatives, so can’t say for sure. My hunch is no, you can’t use anything besides all-purpose flour, because the flour serves the purpose of making both the crust and crumble. I would stick with all-purpose flour OR use a gluten-free all-purpose flour baking substitute if that’s the issue for you.
Absolutely! In fact, they pretty much have to be made in advance because you can’t eat these bars straight out of the oven. They need time to cool and set (around 30 minutes or so). If you try to cut into the bars right away, they’ll fall apart in your hands and will likely scald the roof of your mouth.
However, they keep up to 1 week at room temperature and up to 10 days in the fridge. So yes, make them well in advance if you need to!
Storage and Freezing Instructions
At room temperature: Cover tightly with plastic wrap. Bars will last up to 1 week.
In the fridge: Cover tightly and refrigerate up to 10 days.
In the freezer: These bars freeze incredibly well and will last up to six months if sealed tightly in a freezer bag or freezer-safe container.
Recipe Video Tutorial
The blueberry crumble bars were a major hit! I did use extra-thick oats and they came out great. I really appreciate your explanations of why to use particular ingredients (like don’t use the quick-cook oats because they act like flour in this recipe). Thank you so much for this delicious recipe :)
Cheri
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Blueberry Oatmeal Bars
Ingredients
Crust and Crumble Topping
- ½ cup unsalted butter, melted
- 1 cup all-purpose flour
- ¾ cup old-fashioned oats, (don’t use quick cook or instant, they’re finer and behave like flour and will make mixture too dry)
- ½ cup granulated sugar
- ¼ cup light brown sugar, packed
- pinch salt, optional and to taste
Blueberry Layer
- 12 ounces 2 cups blueberries , (fresh or frozen; I used frozen and didn’t thaw)
- ⅓ cup granulated sugar
- 2 tablespoons lemon juice
- 2 teaspoons cornstarch
Instructions
- Preheat oven to 350F. Line an 8-inch square pan with aluminum foil and spray with cooking spray; set aside. Lining the pan helps with cleanup and is recommended.
Make the Crust and Crumble Topping
- In a large, microwave-safe bowl melt the butter, about 1 minute on high power.
- Add the flour, oats, sugars, optional salt, and stir to combine. Mixture will be dry and sandy with some larger, well-formed crumble pieces.
- Set 1 heaping cup mixture aside to be sprinkled on later as crumble topping.
- Transfer remaining mixture to prepared pan, and using a spatula or your fingers, hard-pack the mixture to create an even, smooth, flat crust; set aside.
Make the Blueberry Layer
- In a large mixing bowl (same one used for crust and crumble is okay), add all ingredients and toss to combine. If sugar hasn’t dissolved fully that’s okay because it liquifies while baking.
- Evenly distribute blueberry mixture over the crust.
- Evenly sprinkle with the reserved heaping 1 cup crumble topping mixture. Before sprinkling, I squeeze the mixture in my palm to encourage bigger crumble pieces to form.
Bake the Bars
- Bake for about 55 minutes, or until edges are set and center has just set. Crumble topping should appear set and very pale golden. I used frozen berries without thawing and the pan was very cold going into the oven. If using fresh berries, baking time will be reduced, but I’m not sure by how much, I’d guess at least 10-15 minutes, possibly less. Bars may take longer than 55 minutes if blueberries are very juicy. Watch your bars, not the clock, when evaluating doneness.
- Place pan on a wire rack and allow bars to cool for at least 30 minutes before slicing and serving. If you try to slice bars before they’ve cooled completely, they’ll be extremely messy and could fall apart.
Video
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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More Desserts Using Blueberries:
Blueberry Pie Bars — Super soft, easy bars with a creamy filling, streusel topping and abundance of juicy blueberries.
Blueberry Crisp — The sweet juicy blueberries contrasted with the crispy and crumbly oat-based topping is just perfect!
Crustless Blueberry Pie – A FAST, crustless, no-mixer dessert that’s perfect for summer entertaining, picnics, or potlucks!! Somewhere in between pie, cake, and blondies is what you get with this FABULOUS blueberry dessert recipe!
Lemon Blueberry Bundt Cake with Lemon Glaze — Almost more berries than cake in this soft, fluffy lemon blueberry bundt cake! The lemon glaze is plate-licking delish!!
Blueberry Muffin Cake — This fast and easy cake tastes like a big buttermilk pancake that ran into a blueberry muffin on the way to the oven.
Blueberry Zucchini Bread— This blueberry zucchini bread is a quick, no-mixer recipe that’s sweet, but not too sweet. Each bite is bursting with fresh blueberries!
Blueberry Cream Cheese Cake — A light and tender blueberry sponge cake stuffed with tangy-sweet cream cheese filling and bursting with juicy blueberries in every bite! An EASY, no-mixer cake recipe that’s sure to be a family FAVORITE!!
Followed recipe verbatim, came out delicious! You’ve done it again, Averie!
Thanks for the 5 star review and glad this was a winner for you!
I just had the first bar. I want to eat the rest of them NOW. They are even better than I thought and was hoping they were going to be. I used salted butter and eliminated the lemon juice, I didn’t make any other changes. I know I will probably be making these more often than I should. Also, they are so easy to make .
I just had the first bar. I want to eat the rest of them NOW. They are even better than I thought and was hoping they were going to be. I used salted butter and eliminated the lemon juice, I didn’t make any other changes. I know I will probably be making these more often than I should. Also, they are so easy to make .
Thanks for the 5 star review and glad that you will be making them often!
I have cut out sugar. Can I make this using Swerve and or Stevia? Those are the only ones I know of not to raise blood sugar. I would attempt this using Almond Flour instead of regular flour as well which will also make it healthier and lower carb. I will play around with this and see if I can make it Whole 30 and/or keto so that I can eat it because it looks too good not to try to make it for my woe. Thanks, I do use your recipes when they fit into my eating plan and have found them wonderful as I am sure this one is, too.
Yes please play around with it. That is the only way you will know for sure. I haven’t tried to modify the recipe from what is written.
these are superb fruity recipes! trouble is, about 50% of adults can’t assume 62 grams of carbohydrates in one serving. please create the same wonderful recipes without high carbohydrates and you’ll have fans for life!
best regards, Julie Stroeve, Minneapolis
I have tried this one with blackberries as I had them in the fridge and I bet it came out not worse than with blueberries.
I have tried this one with blackberries as I had them in the fridge and I bet it came out not worse than with blueberries.
Thanks for the 5 star review and glad it was great with blackberries.
Just made these this weekend. They came out great! Killer recipe. total keeper, Averie. Thanks! I made a second batch using frozen mixed berries (blueberries, cherries, raspberries, and blackberries). That also came out fantastic. With summer just around the corner I’m gonna try it with stone fruits and also a mix of berries and stone fruits. Also going to try using browned butter.
I’m glad these are total keepers for you and you will be making more it sounds like!
These look so good! Do you think they would work with either chopped frozen cherries or diced apples? Also, could I substitute refined coconut oil for the butter?
Not sure on any of your questions since I have not experimented with them. Coconut oil instead of butter though, not really since it will just melt and not lend to making the crumbles this recipe has.
Have made these often! And equally as good with raspberries!
Thanks for the five star review and I’m glad you make these often and with raspberries, too!
Have you ever tried doubling the recipe for a 9×13? Do you think it would turn out? Or be mush in the middle?
I think if you double the recipe and bake it in a 9 x 13 pan you’ll be fine, although I haven’t personally tried it, but I think it will be fine.
These were amazing! I made them exactly how you said except omitted lemon juice and I used a glass 9×7 baking dish. They came out great! This one is bookmarked for sure. Thank you!!
Glad they were amazing and you have the recipe bookmarked!
These are amazing! I love the crumb topping.
I made a half batch using fresh blueberries and cooked for about 40 minutes.
I can’t wait to try again mixing in other berries.
Thanks for the 5 star review and glad they turned out amazing! And yes a very flexible recipe so I hope you enjoying experiments with other fruits and berries!
These are awesome and easy, as everyone claims, but they are basically CANDY. They don’t need to be as sweet or buttery as they are, imo. I left out a quarter of the sugar in the crumble crust, and it’s still way too sweet. Next time I’ll halve the sugar and use at least a quarter less butter. They’ll still be amazing.
Everyone’s preferences for sugar, salt, etc. vary. What one person thinks is candy, another person sees as a breakfast bar that has just the right level of sweetness. To each their own. Glad you enjoyed the recipe!
Do you think I could freeze this and it would thaw nicely?
I’d like to have it Christmas morning.
I’ve made it once before recently and it was a big hit!!
We’re so close to Christmas that if you’re trying to make this for Christmas, I would just keep them covered nicely on your countertop in an airtight container. I would not bother freezing. Freezing is just going to dry things out in the end, and it’s for long-term storage. We’re talking three days here at this point, just keep it at room temperature covered well.
Made this exactly like the recipe! MY HUSBAND and my MOPS group loved them. Has anyone tried them with fresh apple?
Thanks for the 5 star review and glad it was a hit! I have never tried it with fresh apple.
Tasted perfect! Is it 414 calories for each serving for 8 servings? So 3312 for the whole pan?
Yes that is the correct. Although note that nutrition stats are provided as a courtesy and are computer generated.
Just tried this recipe and we love it! So easy to make – one bowl and no mixer – and I don’t have to remember to soften butter ahead of time. I used fresh blueberries that were pretty juicy, so I added a couple of tablespoons of flour to the blueberry mixture to make sure it was thick enough. This is a keeper and will definitely make again and again. Thanks Averie.
Thanks for trying the recipe and I’m glad you love it!