Blueberry Crumble Bars just in time for blueberry season! These bars have a buttery shortbread-like base and juicy blueberry filling. The blueberry layer turns jammy as it's baked. With the crumble being the same as the base, it makes this recipe all the easier! A simple go-to summer recipe!

Nothing says warm weather like fruit bars. The base of these Blueberry Crumble Bars is an oat sugar mixture that comes together with melted butter. It's got a blueberry lemon filling that can be made with either fresh or frozen blueberries.
If you've got 20 minutes to spare you can have these bars baking in your oven!
For more Spring recipes, check out these Cherry Pie Bars or Banana Oatmeal Cookies.
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Why this recipe works
- Juicy blueberry filling.
- Melted butter for immediate baking.
- Buttery shortbread-like base.
- No mixer required.
- 20 minute assembly.
- Serve with warm ice cream for the ultimate dessert.
Key Ingredients
Full recipe and ingredients are in the recipe card below. Feel free to scroll through this section to view certain key ingredients we’re using!
Lemon juice - This is added into the blueberry filling to enhance the tart flavour and balance the sugars.
Blueberries - Frozen blueberries are used. Make sure there is no extra water from the frozen berries. Fresh ones may be used as well.
Brown sugar - I used light brown sugar, but dark brown also works.
Butter - Unsalted butter works best for baking. This is going to be melted.
Quick Oats - I used these ones. Helps achieve that crumble texture we all love. Can be substituted for large flake oats.
Step by Step Instructions
Here is how to make and bake these Blueberry Crumble Bars. You will need an 8×8 square pan lined with parchment paper, a large mixing bowl, a spatula, and a whisk.
Step 1 - Line an 8×8 pan with foil and grease lightly with oil.
Step 2 - In a large bowl, whisk together flour, brown sugar, white sugar, and quick oats.
Step 3 - Add in melted butter (slightly cooled) and egg yolk. Using your hands or a wooden spoon, mix until it forms a crumble texture.
Step 4 - Scoop a cup of the mixture and put it to the side. This will be used as the topping.
Step 5 - Pour the remaining mixture into the prepared square pan and press down firmly using the bottom of a glass or your hand.
Step 6 - In a small bowl, combine frozen blueberries, white sugar, and lemon juice.
Step 7 - Scoop the filling onto the base of the bars. Evenly distribute.
Step 8 - Add the remaining cup of crumble mixture you put aside earlier on top.
Step 9 - Bake for 30-35 minutes or until the top is a nice golden brown. Allow to cool completely before slicing.
Step 10 - Enjoy!
FAQ
Can I use fresh blueberries?
Yes!
Why did my bars turn out soggy?
Make sure you drain the frozen blueberries of any excess water before adding it into your bowl. Take them out in the beginning as you measure and prep all of your ingredients. See video for reference.
Can I freeze Blueberry Crumble Bars?
Yes! But the top will not be crispy when you reheat it.
Expert Baking Tips
Here are five awesome baking tips from my kitchen to yours
- Cooling - The bars can't be sliced warm or else they'll fall apart! You must completely cool them. You can speed this up by placing them in the fridge!
- Doubling the recipe - Baking for a crowd? This recipe may be doubled in a 9x13 pan.
- Fruits - Not a fan of blueberries? No problem! Substitute for any other berries like strawberries, raspberries, blackberries, etc.
- Ice cream - I recommend topping it off with a scoop or two of vanilla ice cream for the ultimate dessert. If you want to serve this dessert warm you may, but just know it will fall apart and turn into a crumble dessert!
- Prepared pan - You must grease the pan with oil. Especially the sides! The filling will stick to any foil that isn't greased and we don't want that!
PS : If you enjoyed this recipe, please make sure to leave a STAR REVIEW down below! I'd love to stay connected on Instagram @taffeybakery! To get more recipes follow me on TikTok @taffeybakery!
Check out these other recipes
- Quick and Easy Cheese Muffins
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Blueberry Crumble Bars
Ingredients
Base & Crumble Topping
- 1/2 cup white sugar
- 1/4 cup brown sugar
- 1 cup flour
- 3/4 cup quick oats
- 1 egg yolk
- 1/2 cup butter melted
Blueberry Filling
- 1/2 cup white sugar
- 3 tbsp lemon juice
- 2 cups frozen blueberries
Instructions
- Preheat the oven to 350°F and lightly grease and line a square pan with foil.
- In a bowl, add brown sugar, white sugar, flour, and quick oats. Whisk until mixed.1/2 cup white sugar, 1/4 cup brown sugar, 1 cup flour, 3/4 cup quick oats
- Add in egg yolk and melted butter and continue on mixing using a wooden spoon or your hands. It will turn into a crumbly form.1 egg yolk, 1/2 cup butter
- Set aside 1 cup of the dough. This will be for the topping.
- Transfer the rest of the dough into the pan and press down firmly with your hands or the bottom of a glass. Ensure the entire pan is covered.
- In a separate bowl, mix together the blueberries, white sugar, and lemon juice with a spoon.1/2 cup white sugar, 3 tbsp lemon juice, 2 cups frozen blueberries
- Scoop the filling onto the base of the bars. Evenly distribute.
- Add the remaining crumble mixture on top over the berry layer.
- Bake in preheated oven for 30-35 minutes or until the top begins to become a golden brown colour.
- Allow to cool completely before slicing. You may speed up this process by placing it into the fridge.
- Store cooled bars in an airtight container in refrigerator.
- Enjoy!
Julie says
Can fresh blueberries be used?!
Ania says
Yes!
Barbara says
Can old-fashioned oats be used?
Ania says
Yes!