These Blueberry Oatmeal Bars are wise teachers in the beauty of simplicity in cooking and baking. I am often tempted by the idea that the more ingredients I add to a recipe, the better the dish will taste. These easy blueberry oatmeal bars prove me wrong with every bite. They couldn’t be easier to make, I’d wager you have all the ingredients you need to make them in your pantry right now, and the only thing I could possibly add to make them taste even better is a scoop of vanilla ice cream!
This idea that simple is often better in cooking is a lesson I know I’m going to keep learning over and over. I might even have to eat a few extra blueberry oat bars to continually refresh my memory. It’s a hard order, but life lessons are life lessons, and it’s important that I stay sharp.
I adapted these Blueberry Oatmeal Bars from one of the all-time most popular recipes on my site, these healthy Strawberry Oatmeal Bars. Both are fresh, fruity, and showered in buttery crumble topping. Both need only one bowl to prepare. Both even clock in at approximately 100 calories. Swap that ice cream I mentioned earlier for a scoop of Greek yogurt, and you can be eating baked strawberry or baked blueberry bars at breakfast.
Although I’m not going to be committing myself to a single fruit bar recipe for the rest of my life anytime soon (particularly with such delights as Caramel Apple Bars and Cherry Bars to consider), these Blueberry Oatmeal Bars do have a serious advantage over any other oatmeal crumble bar I’ve ever baked: blueberries take exactly zero prep work.
Blueberries don’t need to be sliced like strawberries, pitted like cherries, or peeled like apples. In fact, you don’t need to do another blessed thing, other than prevent yourself from eating them all before you’ve finished the recipe.
It feels especially appropriate to be sharing this Blueberry Oatmeal Bar recipe today, because I’m currently in a place that does simplicity perhaps better than any other: Italy. In case you missed Tuesday’s update, I’m spending five days in Verona learning all about how fresh pasta is made, then heading to Paris for a few days to revisit all of my favorite Parisian bakeries and chocolate shops. ? Be sure to follow my Instagram (I’ll be sharing both posts and stories), and I’ll eventually be sharing a recap of my trip here too.
Wishing you all a sweet weekend, with a pan of Blueberry Oatmeal Bars to go along with it!
Recipe Adaptations
- To Make Gluten Free. Be sure to use certified gluten-free oats like these and swap the white whole wheat flour for a 1:1 baking blend (I’ve had good luck with this one).
- To Use Frozen Blueberries. I have not tried this recipe with frozen, thawed blueberries, but I think that it would work. Be sure to thaw the blueberries completely first.
- To Double the Recipe. The recipe can be doubled and baked in a 9×13-inch baking pan. The bars will be a bit thicker but still delicious.
More Blueberry Recipes
Recommended Tools to Make This Recipe
- Favorite 8×8 inch baking pan
- Parchment paper (I love these pre-cut sheets)
Blueberry Oatmeal Bars
Ingredients
FOR THE BLUEBERRY OATMEAL BARS:
- 1 cup old-fashioned rolled oats gluten free if needed
- 3/4 cup white whole wheat flour or substitute all-purpose flour or, to make gluten free, 1:1 baking flour
- 1/3 cup light brown sugar
- 1/2 teaspoon ground cinnamon
- 1/4 teaspoon kosher salt
- 6 tablespoons unsalted butter melted (or substitute melted coconut oil to make vegan/dairy free)
- 2 cups fresh blueberries* about 10 ounces
- 1 teaspoon cornstarch
- 1 tablespoon freshly squeezed lemon juice from about 1/2 small lemon
- 1 tablespoon granulated sugar divided
FOR THE VANILLA GLAZE (OPTIONAL BUT DELICIOUS, ESPECIALLY IF YOU PREFER A SWEETER BAR):
- 1/2 cup powdered sugar sifted
- 1/2 teaspoon pure vanilla extract
- 1 tablespoon milk any kind you like
Instructions
- Place a rack in the center of your oven and heat to 375 degrees F. Line an 8x8-inch baking pan with parchment paper so that the paper overhangs two sides like handles.
- In a medium bowl, combine the oats, white whole wheat flour, brown sugar, cinnamon, and salt. Pour in the melted butter and stir until it forms clumps and the dry ingredients are evenly moistened. Set aside 1/2 cup of the crumble mixture, then press the rest into an even layer in the bottom of the prepared pan.
- Scatter half of the blueberries over the crust. Sprinkle the cornstarch evenly over the top, then sprinkle on the lemon juice and 1/2 tablespoon granulated sugar. Scatter on the remaining berries, then the remaining 1/2 tablespoon sugar. Sprinkle the reserved crumbs evenly over the top. You will have some fruit showing through.
- Bake the bars for 30 to 40 minutes, until the fruit is bubbly and the crumb topping smells toasty and looks golden. Place the pan on a wire rack to cool completely (you can speed this process along in the refrigerator).
- While the bars cool, prepare the glaze: in a medium bowl, briskly whisk together the powdered sugar, vanilla, and milk until smooth. Feel free to add more milk if a thinner consistency is desired. Using the parchment paper handles, lift the bars from the pan. Drizzle with the glaze, slice, and serve.
Notes
- *I have not tried this recipe with frozen, thawed blueberries, but I think that it would work. Be sure to thaw the blueberries completely first.
- The recipe can be doubled and baked in a 9x13-inch baking pan. The bars will be a bit thicker but still delicious.
- To make the bars gluten free, substitute the white whole wheat flour with a 1:1 baking mix like this one.
- Store leftovers in the refrigerator for up to 5 days.
- To freeze, let the bars cool completely and do not glaze. Wrap tightly in plastic before placing in the freezer. Let thaw in the refrigerator and top with glaze before serving. (Bars can be frozen already glazed if needed.)
Nutrition
Join today and start saving your favorite recipes
Create an account to easily save your favorite projects and tutorials.
Register
I made the strawberry bars and loved them! Super excited to try these next, since blueberries are soon in season in Maryland :)
One question, do you think these would work with less butter or is this much needed to hold the crumble together? Have some cholesterol-watchers in the family.
Hi Sukhi, so glad you enjoyed the strawberry bars. For the butter, you need to keep the same amount but you can swap it out with coconut oil if that helps! Let me know how it goes!
I made these blueberry oat squares and they were great! The recipe is easy, and I followed it exactly as written with the icing. Next time, I think that I will increase the amount of crumbs on top because they were very tasty. I placed them in the refrigerator and they lasted 5 days. Thanks so much for this recipe.
Hi Diana! So glad you enjoyed the recipe! Thank you for this kind review!
I got up early and made these for breakfast. Blueberries are abundant where I live and I was searching for recipes to use all the blueberries I had (instead of just smoothies!) this recipe looked so good! My teenage son loves them! I made these bars exactly how you listed and they are seriously my favorite! I’m going to try it with other fruit as well, strawberries you say? I’m in! Thank you so much!!
Hi Marianne! So glad you enjoyed them! Thank you for this kind review!
I was not patient enough when I found this recipe. I used frozen blueberries. They turned out great! I will hold off next time and let them thaw, or use fresh berries. But 35 minutes in the oven was plenty and they turned out amazing
Hi Kristy! Thanks for the feedback! So glad you enjoyed the recipe! Thank you for this kind review!
These bars are easy and delicious! Followed the recipe exactly and they are always a big hit! I can’t comment as to how long they last in the fridge because they don’t last 24 hours in my house!
Hi Regina! Hahah! Yep, they never last long for us either! So glad you enjoyed this recipe! Thank you for this kind review!
Whenever I see just one square of these Oatmeal Blueberry Bars in the refrigerator, I know it is time to make more! Due to my younger son’s dietary requirements, I make this with 1:1 gluten-free flour (Bob’s Red Mill or King Arthur Flour) and a plant based-butter (MELT). Every time = a success! Now that my son has returned to college, I’ve been making with white whole wheat flour – of course, just as delicious – and will continue to do so until my older son leaves to continue his studies. For any readers that are curious about reducing the sugar, I use 1-1/2 tsp per “layer” and as my boys prefer, no icing. Thank you Erin for all your delicious recipes. You are a household name around here…
Hi Nancy! That makes me so happy to hear! Thank you for the feedback and for this kind review!
These are absolutely delicious.
Can I substitute the sugar for stevia or can sugar? Will it make a difference in texture or taste?
Hi Lauren! I have only tested the recipe as written. If you decided to experiment, let me know how it goes!
Hi Erin
I’ve made these bars and they are delicious, I made a batch and they came out dry, grainy and I made them too thick.
How do I prevent this from happening and how do I fix them? Do I add honey and rebake them?
Hi Lauren, I’m sorry to hear that these didn’t hold up well. Another reader mentioned that she mashes some of the blueberries first to help the bars bind together better, so that might help. I’m so happy you still were able to enjoy them!
Tastes lovely but did not bind together Just crumbly unable to cut into pieces
Hi Di! I’m sorry to hear that these didn’t hold up well. Another reader mentioned that she mashes some of the blueberries first to help the bars bind together better, so that might help. I’m so happy you still were able to enjoy them!
Just tasted these as they’ve been cooking and teasing me for about an hour and I couldn’t wait any longer! They are delicious! Hubby loves them too, which is a bonus for me! He LOVES sweets, so I’m always looking for healthier options to satisfy him. I had some leftover blueberries that I needed something to do with before they went bad. This recipe was easy to follow, with easy ingredients that I had on hand. Only thing I did different than the recipe was mix the sugar and lemon juice before adding on top. Next time I may also mix in the cornstarch to that for more even distribution. Great recipe!!
Hi Danielle! So glad you enjoyed the recipe! Thank you for this kind review!
I make them again and again. Thank you!
Hi Les! So glad you enjoyed the bars! Thank you for this kind review!
I made these blueberry bars for my husband yesterday and they were excellent and easy! Another hit from Erin.
Hi Robbie! So glad you enjoyed the recipe! Thank you for this kind review!
Had a lot of blueberries I didn’t know what to do with so I gave this recipe a shot. Great tasting healthy snack!
Hi Rose! So glad you enjoyed the recipe! Thank you for this kind review!
I have made these bars several times and they are delicious. I don’t bother with the icing as they are sweet enough on their own. One question, why does the recipe call for 2 cups of blueberry but has 10 ounces next to it? I double the recipe, so have been using almost 4 cups of blueberries. Thanks
Hi Diane, that is for the readers who weigh their blueberries instead of measuring in cups.
I made this with frozen blueberries. I didn’t make the icing and it tastes amazing!!! Super yum. I will make this again. I had to cook it a lot longer as my berries were frozen. I think if you thaw them first it would cook around the same time. It took about an hour or so. I checked it every 10 minutes and once the blueberries bubbled i pulled it out
Hi Lou! So glad you enjoyed the recipe! Thank you for this kind review!
Wow…this exactly
what I was looking for I’m a breakfast blueberry treat! Not bready at all…perfect texture and flavor. I mixed in raspberries from my garden too!
Hi Bridget! So glad you enjoyed it! Thank you for this kind review!