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Amazingly easy and delicious, these Blueberry Crumble Bars are the perfect amount of buttery crumble and sweet filling and are easily prepared year-round with fresh or frozen blueberries.
Buttery toppings and sweet pie fillings are a favorite dessert here at The Forked Spoon, including Easy Lemon Bars, Strawberry Rhubarb Cobbler, and Blackberry and Blueberry Galette with Rosemary.
Table of Contents
I keep going back and forth on how to properly start a post for the most amazing Blueberry Crumble Bars you will ever make in your whole life. Do I start with small talk first? Or just start talking about the food?
Since most (translation- all) of you are here for the food, let’s start there.
And with the basics.
Key Ingredients
- All-purpose flour
- Cold butter
- Eggs
- Lemons- juice, and zest
- BLUEBERRIES
Definitely not diet food, but that’s ok. I mean, we’re not here for diet food today.
As far as flour goes, I used all-purpose flour. It’s like the white bread of flours and my personal preference for this particular recipe. That said, I suspect that these blueberry crumble bars would taste fantastic if you mixed the all-purpose flour with whole wheat flour or almond flour.
Fresh or Frozen Blueberries?
I have two answers to this question-
- If you want the best, fresh, ripe blueberry flavor, then fresh in-season blueberries are ideal. You can’t gauge taste and ripeness when you purchase frozen blueberries. That said, it’s not always berry season.
- Cost. Big, beautiful, ripe, in-season berries are expensive. So, unless they grow wild in your backyard, making a single sheet of Blueberry Crumble Bars or a couple of blueberry pies is expensive. For me, a person who already spends way too much on groceries, I am willing to compromise a teeny bit of flavor and use frozen berries.
So just in case you didn’t catch that, these Blueberry Crumble Bars shown here are made with frozen blueberries.
Why these are so Fantastic
- They are, quite honestly, the easiest thing you will ever make.
- They are super versatile. Meaning what exactly? If you don’t have blueberries, use what you’ve got on hand or whatever’s in season.
- Blueberry crumb bars are easy to store and transport, which makes them the perfect party or potluck treat!
- There is no need for fancy equipment when making these blueberry pie bars.
- Which reminds me…pie is a thing of the past thanks to these beauties.
If you do plan to share your beautiful blueberry crumb bars with friends and family and you plan to get all prepped and ready ahead of time, I HIGHLY recommend hiding them from everyone in your house. Actually, in the case of these bars, it’s just better to triple the recipe because unless you hate delicious blueberry pie, there is no way you’ll be able to keep these from even yourself.
And I know this because this happened to me.
Usually, it’s the husband’s fault when treats go missing, but in the case of these sweet and buttery bars, well… that was all me.
Equipment needed
Are you ready for this super long list?
- Mixing bowls
- Parchment paper
- A 9×13-inch pan. I used this 9 x 13-inch pan and love love love it. Yes, the glue is a pain in the you-know-what to remove, but it does eventually come off.
If you love these bars, you may also enjoy
Blueberry Scones with Lemon Glaze
>FIND MORE DESSERT RECIPES HERE<<
Blueberry Crumble Bars Recipe
Ingredients
- 1 cup white sugar
- 1 teaspoon baking powder
- 3 cups all-purpose flour
- 1 cup cold unsalted butter, (2 sticks)
- 1 large egg
- ½ teaspoon salt
- 2 lemons zested
- 2 lemons juiced
- 5 cups fresh or frozen blueberries
- ½ cup white sugar
- 4 teaspoon cornstarch
Instructions
- Preheat oven to 375 degrees F and grease a 9×13 inch baking pan (I also lined my pan with parchment paper for easy transfer and cutting).
- In a large bowl, mix together the 3 cups of flour, 1 cup of sugar and baking powder. Mix in salt and lemon zest. Using a large fork or pastry cutter, blend the butter and egg into the flour (you could also do this is a food processor, but be careful to slowly pulse until just incorporated). The dough will be very crumbly. Transfer half the dough to your prepared pan and pat firmly until crust is uniform.
- In a separate bowl, stir together the 1/2 cup sugar, cornstarch, and lemon juice. Mix in the blueberries. Transfer the blueberry mixture over the top of the prepared crust. Finally, crumble remaining dough over the top of the berry layer.
- Bake in preheated oven for approximately 45 minutes, or until top is slightly brown. Remove from the oven and allow bars to cool completely before cutting into squares, or, better yet, store in the refrigerator for a few hours before serving (it makes slicing a breeze and, in my opinion, they are best cold).
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
These are absolutely delicious. I’ve made them several times and always get rave reviews.
Thank you so much for your kind words! I’m so happy to hear that you’ve made them several times and that they’re always a hit.
How do I prepare the frozen blueberries before adding them?
Thaw? Drain?
Great question! If you’re using frozen blueberries, there’s no need to thaw them first—just add them straight from the freezer. However, if they’re covered in a lot of ice crystals, give them a quick rinse in cold water and gently pat them dry to remove excess moisture. This helps prevent the bars from getting too soggy.
I absolutely love that I can use frozen blueberries. This is a huge family favorite!
I’m so happy to hear that—especially that it’s become a family favorite! And yes, being able to use frozen blueberries makes it so much easier to enjoy year-round. Thanks so much for your kind comment! 💙
Delicious!! Loved using frozen blueberries and the added lemon. Definitely going to make this again
So glad you loved them! Frozen blueberries with lemon are such a great combo, thanks for sharing!
I wish you would put the lemon juice in a measurement form. There are many different sizes of lemons.
Thank you
Thank you for your feedback! You’re absolutely right about the variation in lemon sizes. For clarity and consistency in the recipe, using about 4 tablespoons of lemon juice, which is roughly the amount you’d get from juicing two medium lemons, is ideal. This amount perfectly balances the flavors in the blueberry crumble bars. Thank you again for your input, and happy baking!
great yummy
Thanks for the feedback and rating, Dianne 🙂
I’ve made this many times for potlucks and it always comes out great; never any leftovers. Could I use the same recipe with apples or would they not have enough juice?
Can I use flour in place of cornstarch?
I used less sugar in the batter since I didn’t want them too sweet but still they turned out sweet
My only issue was since I used frozen blueberries they were a lot soggier that I expected and the entire top turned purple from the juice
This recipe is the best version of Blueberry Crumble Bars I’ve made. The bottom was crisp but not too crunchy – firm enough to hold the bar shape and a delectable texture. The cornstarch did indeed help make the juices thick and not soggy the bottom! The only addition I made was to sprinkle 1/2 pkg of Vanilla Sugar over the crumb top, which is certainly not necessary. It just gives a smidge of vanilla taste, a little sparkly appearance, and firms up the topping a tad. Again, this is the best Blueberry Crumble Bar recipe I’ve found, especially since it makes decently thick bars and fills a 9×13 pan! Plenty for a crowd, or to stash some aside for yourself before plating them for guests! LOL
Thanks for the best feedback and rating 🙂
Sounds delicious! Just one question: does the liquid from the blueberries as they bake make the cookie bottom soggy or does the corn starch prevent that? Will be making this recipe soon. Thanks!
When making blueberry crumble bars, the liquid released by the blueberries during baking can indeed make the cookie bottom soggy if not handled properly. However, incorporating cornstarch with the blueberries before baking helps to thicken the juices that are released as the blueberries cook. This thickening effect prevents the liquid from seeping down and making the cookie base soggy. The cornstarch acts as a binding agent, absorbing moisture and helping to maintain a firmer, crisper bottom layer. For best results, make sure to evenly distribute the cornstarch-coated blueberries over the cookie base, and ensure that the cornstarch is well-integrated with the blueberries to avoid any clumping. Enjoy baking your blueberry crumble bars!