Blueberry Crumb Bars

Loaded with fresh blueberries and topped with a buttery crumb topping, these easy Blueberry Bars are the perfect summer dessert. Make a batch and share them with friends at cookouts and potlucks!

Blueberries are amazing when they are in season! Try my reader’s favorite Lemon Blueberry Bread and my Blueberry Sour Cream Coffee Cake is perfect for an afternoon snack!

Blueberry Bars sliced on a white chopping board next to a knife.

These Blueberry Crumbs Bars are incredibly easy to make. You only need two bowls and a couple of minutes to make these bars!

I use fresh blueberries and toss them with lemon juice, sugar, and cornstarch. Sandwiched between the blueberry filling is the crumb topping. It goes on both the bottom and top of the bars. The crumb topping is by far the BEST part! Crunchy, buttery with the perfect amount of sweetness.

Ingredients for Blueberry Bars

  • Blueberries: Fresh blueberries are ideal for this recipe, however, frozen will work as well. Keep in mind that frozen will take a little longer in the oven!
  • Butter: Nothing beats a buttery crumb topping so this recipe has plenty of butter in it!
  • Oats & flour: Old fashioned oats and all-purpose flour are the base ingredients for the crumb topping. The oats crisp up nicely for that amazing crunch we all love!
  • Sugar: I opted for brown sugar in this recipe as it adds a hint of caramel flavor along with the sweetness.
  • Cinnamon: Just a hint of warmth and spice, cinnamon is a must for the crumb topping.
  • Lemon juice: For a slight tart kick I added a little lemon juice. Lemon and blueberry flavors are made for each other!
  • Cornstarch: This thickens up the blueberry sauce in these blueberry bars so that it’s not too runny!

How to make Blueberry Bars

  • Start by making the crumb topping. In a medium bowl combine melted butter, flour, oats, sugar, cinnamon, and salt. Stir until the mixture resembles wet sand and is clumpy. Set aside 1 cup of the mixture.
  • Transfer the remaining mixture into the prepared pan and pat down with your fingers or the backside of a spoon, set aside.
  • In a medium bowl combine blueberries, sugar, lemon juice, and cornstarch. Toss to combine. Layer the blueberry mixture over the crust.
  • Sprinkle the remaining cup of crumb over the bars. Bake for 30 minutes in a 350-degree oven for fresh blueberries or 50 minutes for frozen or until the center is set.
  • Allow the blueberry bars to cool completely on a wire rack before slicing.

Blueberry Bars in a white baking dish.

Tips for making these bars

  • I like to make sure the blueberry bars cool completely before cutting into them. If not it will make a gooey mess. I like to pop them in the freezer for 30 minutes then slice them. It makes cutting them so much easier!
  • You can make this recipe with either fresh or frozen blueberries. Just keep in mind that frozen blueberries will take a little longer in the oven.
  • For an added crunch chopped pecans or walnuts can be added.
  • You can do a mix of blueberry and any other type of fruit you have on hand. Raspberries, blackberries, strawberries, or peaches would all be great for this recipe!

Frequently Asked Questions

  • Can I freeze blueberry crumb bars? Yes, absolutely! After the blueberry bars have completely cooled, store them in an airtight container in the freezer for up to 4 months. Thaw them completely before consuming them. You can also reheat them in the oven to make them extra crunchy again!
  • What are crumb bars? Crumb bars are a fruit-filled baked dessert with a layer of crumb on both the bottom and the top. The crumb is made of oats, flour, butter, sugar, and cinnamon, and the fruit layer can be many different kinds of fruit like blueberries, strawberries, or peaches.

What can I do with a bunch of blueberries?

I happen to love cooking with blueberries! Other than making these delicious Blueberry Bars, here are my favorite ways to use them up:

Easy Lemon Blueberry Bars sliced on a white chopping board next to a knife.

Here are more delicious dessert recipes to try!

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Blueberry Crumb Bars

Prep Time: 15 minutes
Cook Time: 50 minutes
Total Time: 1 hour 5 minutes
Servings: 9 bars
Blueberry Crumb Bars. Fresh blueberries sandwiched between a buttery crumb topping.

Ingredients

  • ½ cup unsalted butter melted
  • 1 cup all purpose flour
  • ¾ cup old fashioned oats
  • ¾ cup light brown sugar
  • ½ teaspoon cinnamon
  • ¼ teaspoon salt
  • 2 cups blueberries
  • ¼ cup light brown sugar
  • 2 tablespoons lemon juice
  • 2 teaspoons cornstarch

Instructions

  • Preheat oven to 350 degrees. Grease an 8 x 8 pan with cooking spray.
  • In a medium bowl combine melted butter, flour, oats, sugar, cinnamon and salt. Stir until the mixture resembles wet sand and is clumpy.
  • Set aside 1 cup of the mixture.
  • Transfer the remaining mixture into the prepared pan and pat down with your fingers or the backside of a spoon, set aside.
  • In a medium bowl combine blueberries, sugar, lemon juice and cornstarch. Toss to combine.
  • Layer the blueberry mixture over the crust.
  • Sprinkle the remaining cup of crumb over the bars.
  • Bake for 30 minutes for fresh blueberries 50 minutes for frozen or until the center is set.
  • Allow the bars to cool completely on a wire rack before slicing.
  • I let them cool then place in the freezer for 15-30 minute to make it easier to cut. If you cut before they are cool it will make a mess.
Nutrition Facts
Blueberry Crumb Bars
Amount Per Serving
Calories 281 Calories from Fat 99
% Daily Value*
Fat 11g17%
Saturated Fat 7g44%
Cholesterol 27mg9%
Sodium 74mg3%
Potassium 97mg3%
Carbohydrates 45g15%
Fiber 2g8%
Sugar 27g30%
Protein 3g6%
Vitamin A 335IU7%
Vitamin C 4.5mg5%
Calcium 31mg3%
Iron 1.2mg7%
* Percent Daily Values are based on a 2000 calorie diet.
Course: Dessert
Cuisine: American
Keyword: Blueberry Crumb Bars

Originally published Sept 15, 2017

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