Blueberry Oatmeal Crumble Bars

I was going to call these blueberry breakfast bars. Or blueberry snack bars.

But anytime you feel like eating juicy blueberries with buttery oat crumbles is the kind of bar they are.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

It’s an easy, one bowl, no mixer recipe that takes just minutes to make. I adapted the recipe from 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 crumble topping are one in the same. Love it when that happens so there’s one less step and one less bowl to wash.


Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

I eliminated the Greek yogurt, sugar, and egg from the filling and kept the focus on the blueberries.

The 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.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

They’re soft and tender, yet slightly chewy from the oats, and I’m a sucker for anything with a crumble topping.

My daughter said they’re one of the best ‘desserts’ I’ve made in a long time. I made the bars on a Sunday and had breakfast ready to grab-and-go for her for the week. One less thing to worry about on busy weekday mornings. Loved that.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

Print Recipe

Blueberry Oatmeal Crumble Bars

An easy, one bowl, no-mixer recipe that takes just minutes to make. The crust and crumble topping are one in the same so there’s one less step and one less bowl to wash. The bars aren't overly sweet and the blueberry flavor shines beautifully, making them 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. I made the bars on a Sunday and had breakfast ready to grab-and-go for the week.

Yield: one 8x8 pan, 8 generous wedges

Prep Time: 10 minutes

Cook Time: about 55 minutes

Total Time: about 90 minutes, for cooling


Crust and Crumble Topping
1/2 cup (1 stick) unsalted butter, melted
1 cup all-purpose flour
3/4 cup old-fashioned whole-rolled oats (don't use quick cook or instant, they're finer and behave like flour and will make mixture too dry)
1/2 cup granulated sugar
1/4 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)
1/3 cup granulated sugar
2 tablespoons lemon juice
2 teaspoons cornstarch


  1. 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.
  2. Crust and Crumble Topping - In a large, microwave-safe bowl melt the butter, about 1 minute on high power.
  3. Add the flour, oats, sugars, optional salt, and stir to combine. Mixture will be dry and sandy with some larger, well-formed crumble pieces.
  4. Set 1 heaping cup mixture aside to be sprinkled on later as crumble topping.
  5. 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.
  6. 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.
  7. Evenly distribute blueberry mixture over the crust.
  8. 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.
  9. 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. Bars will keep airtight at room temperature for up to 1 week, in the fridge for up to 10 days, or in the freezer for up to 6 months.

Adapted from Blueberry Pie Bars

Only Eats

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    These bars, OMG. Crust, blueberries, CRUMBLE. The best things ever!

    • You know it. Crumble to the rescue :) And I remember reading this comment last night as I was walking out the door and just now am getting around to replying. What a busy 24 hours I’ve had :)

  2. This recipe ist just amazing!! Unfortunately there’s a lot of sugar inside, but i can exchange it, so thanks a lot!!

  3. The pie looks delicious, but the recipe is kind of hard… I’m not sure if I could make it.

  4. LOVE it when crust and crumble are one and the same. It’s pretty much the best deal ever.
    I love your blueberry version. And it’s so versatile, too! You can try it with raspberry (ooh, and chocolate chunks) or strawberry when July rolls around. Such a great snack!

    • pretty much the best deal ever <--- Amen to one bowl and one-mixture recipes! Such a timesaver! And totally versatile with other berries/fruit! I wish it was summer produce season right now and I'd have a field day!

  5. I just bought a bag of frozen blueberries and now I know exactly what to do with them. I love crumble toppings both sweet and savory.

  6. Ship me a batch of these babies and no one gets hurt.
    Seriously though, blueberries and crumbly topping in one bowl?! ALL OVER THAT. Pinning!

  7. Oh my, blueberries! I want these bars.

  8. One bowl bars are definitely a winner in my book! I love that you cut these into slices, Averie! Looks perfect! Pinned!

  9. I have some frozen pie cherries that have needed a home. I think they are going to be very happy they have found their recipe. Thanks.

  10. Crumble bars are the best. I can imagine how juicy the blueberry filling is, and I would definitely like to eat this for breakfast!

  11. Just stunning! Blueberry anything is a win in my book. And all that gorgeous crumble on top is making my mouth water!

  12. An oatmeal crust and crumble– better than pie and cobbler! This looks yummy and could work so well with different fruits and berries.

  13. I absolutely love this! Blueberries and oatmeal go so well together and with a crumble layer on top it must be delicious. I am going to try these for sure!

  14. I just made the Raspberry Chia Oat Bars from Oh She Glows, and those were pretty tasty, but I’m definitely making these for my next batch of oat bars- those blueberries just look too yummy!

  15. It’s definitely the time of year to start working through our freezer produce. We have lots of frozen blueberries (cherries, too) and this sounds like a perfect use of them. From the other comments, I see I’m not the only one who notices the potential for using other fruits with this recipe. :)

  16. These look great! I, too, am a sucker for a good crumble. And I love how the filling is simply all fruit (and a little sugar!) Love it!

  17. When I saw this this morning it was fate! I had been complaining that I had half a tub of fresh blueberries that needed to be used up, and now I have this merrily baking away, and it smells awesome!

  18. yum yum yum! The perfect breakfast bar ever!

  19. Oh my, I’m for sure making these for breakfast this weekend!

  20. This looks delicious! Blueberries are such a great fruit for this dish.

  21. First recipe I’ve tried from your site, and I am in love!

  22. I like this kind of cake :)

  23. OMGOODNESS that looks beautifully delicious! I am so making this once I get some blueberries. My favorite part next to blueberries are crumb toppings! :) Thanks for sharing!

  24. We always have frozen blueberries in our freeze for morning smoothies and oatmeal. I need to give these a try! Jorge loves fruit bars.

  25. Perfection and picture are fantastic!!

  26. OMG! Do you know I actually thought about writing you to ask if you had a recipe for some blueberry oat bars?! I used to get something similar from Peet’s but they were blueberry-peach and they were SO good! I so look forward to trying these! Thank you!

  27. Everything looks delicious! But blueberry Pie Bars are my favourite! Can’t wait to try this recipe! Thanks for sharing <3

  28. Beautiful photographs as usual! I love blueberries. Last summer, I went to the orchard alone and picked blueberries for at least an hour. It’s such a relaxing (and delicious) time.

  29. These are awesome on all fronts. One bowl, BLUEBERRY, same bottom as top. YUM. Pinning :)

  30. Oooh you’re getting me all excited about the prospect of summer and blueberries and fresh fruit….which is a LONG way off for us in Canada :( I’ll have to settle for these delicious looking bars. Love that crumble topping, these look just perfect!

  31. One of the best desserts? That’s high praise coming from your daughter! I can totally see why too. I’d claim every single bit of crumble for myself… Sorry everyone else, you get naked blueberry bars! :)

  32. Just made these last night to bring to a breakfast potluck this morning, and they turned out fantastic! – Just as you pictured them. I have Celiac, so I made them gluten-free by using Trader Joe’s gluten-free oats and Cup4Cup flour. No one was the wiser. ;) I can’t wait to try them with raspberry or cherry in the filling next! Such a great grab and go breakfast! And it’s awesome that it uses staples, so I foresee this having a regular spot in my breakfast rotation.

    • Thanks for trying the recipe and I’m glad it came out great for you AND that you were able to keep them GF with TJs GF oats and Cup4Cup. That’s great to hear! And I bet raspberry or cherry filling would be super good! (or peaches/nectarines in the summer!) If you try other variations/fruits, LMK what you do and try!

  33. Great recipe…I have been thinking about making something like this! I have fresh home made blackberry jam, do you think that would be fine to substitute the blueberry sauce with the blackberry jam? I don’t want to waste it and I think this could be the perfect recipe for this?

  34. I made these the other and as in all your other recipes I have tried, these came out perfect!

  35. Averie, these look wonderful! I love blueberries and oatmeal and crumb topping is the best! Pinning and putting on the list to try!

  36. what do you think about leaving the lemon juice out? My son loves blueberries but he is sensitive to citrus.

    • In your situation, I think you have to leave it out! And that things will probably be okay. The lemon juice helps the filling set up a bit but it isn’t a pie and hopefully a forgiving recipe; although I haven’t tried leaving it out. LMK if you do!

  37. Do you know how many calories are in each square? Looks amazing btw. Hope to make these soon. 

  38. Susan Vantrojen Reply

    A friend served these and they were delish.  I begged her for the recipe, followed it exactly and failed.  I foiled and greased the pan, they stuck.  My crust was chewy, I don’t think hers was. We ate them but I want a do over.  Do you have any idea what I did wrong?

    • It’s really hard to say what you did and where you went wrong. Maybe since your friend made them and they were great, watch how she made them and see if that’s what you did. I use heavy-duty non-stick Reynold’s foil and PAM cooking spray and I really spray the foil well and never ever have issues. That will take care of that part at least. It’s just so hard to troubleshoot from afar. Thanks for trying the recipe.

  39. Laurie Selwitz Reply

    These are delicious – and easy!! My only comment is that I seemed to have too much filling – so I made them again and did the crust 1 1/2 times so the crust was a little thicker and the top covered the blueberries just a little more, easier to pick up and eat! I see myself making these a LOT!!!!!!

    • Thanks for trying the recipe and I’m glad you enjoyed them. I think filling amounts/yields can vary because of the blueberries; fresh, frozen, tiny berries, bigger ones, etc. Glad you found something that worked for you and made them easier to carry.

  40. Laurie Selwitz Reply

    Susan V – mine stuck on the foil as well – forgot about that part! So I just sprayed glass dish and after they cooled I put them in the refrigerator and they cut easily and were perfect!

  41. I put all the ingredients in a calorie calculator and it looks like a serving is around 310 case anyone else was wondering

  42. Beverly Whalen Reply

    Love this easy and delicious recipe.  My boyfriend east blueberries every morning in his cereal.  Great change of pace.. Tks much.

  43. Yum! These look delicious! Going on my grocery list right now :)

  44. These were delicious!!!! So yummy AND easy!! I found that they were a little gooey and hard to handle (not that that’s important compared to the taste ;) ) so I might make more of the crumble next time… and there WILL be a next time!

  45. I was a little unsure of what you mean by “set up” I felt like I had some pretty large blueberries so I am keeping it in the oven a bit longer. I don’t want it falling apart, but then again I also don’t want to burn it. They smell awesome can’t wait for them to get out of the oven and cooled so I can try one!

    • Set up – not jiggly, runny, overly loose. Not sure what more I can say :)

      Use your best judgment and baking time will vary based on the berries. You never know how juicy, big/small, etc. blueberries will be. Enjoy!!

  46. I just made these as a Father’s Day gift for my blueberry-loving-dad and they turned out well! I had rather large, fresh berries, so I would do the same as others have mentioned and possibly double the crust portion next time for a better crust to fruit ratio (personal preference). I added cinnamon to the crust and would definitely recommend the addition of salt to the crumble/crust as well to round out the flavor. I also added some vanilla to the blueberry mixture, and next time will increase the vanilla and decrease the lemon juice as my berries were on the tart side and the finished product came out with a little bit of a pucker! With the fresh berries, my bars were bubbling and golden at 40 mins in the oven. I’m thinking a layer of cream cheese, vanilla, and sugar would go splendidly in this recipe, as well (similar to your Greek yogurt addition in your other recipe)! For those who ended up with a chewy crust, mine crisped up when I put the bars in the fridge for an hour; they were great cold.  Thanks! 

  47. Cecilia J Ralson Reply

    I was super excited to try these delicious looking and easy recipe, however mine never set up. And I followed the recipe EXACTLY as written. It required a good hour in the fridge just to get it cut into somewhat pieces. Tasted absolutely DELICIOUS, just not very pretty, like at all. :-/

    • The think about berries and fruits, i.e. Mother Nature, is that no two are alike and some are just very juicy and it sounds like yours were very juicy, hence the setting up issues. I’m glad it tasted absolutely delicious despite not being as set as mine but I personally adore super juicy blueberry desserts and would have loved yours I bet too!

  48. Alicia Johansen Reply

    I’ve been waiting to try this recipe for a while now. Finally did it and they turned out to be delicious! They were a little difficult to get out of the pan and could use lees sugar but were very simple and easy. Turned out fabulously the first try which is always nice.

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