Blueberry Pie Bars with Oatmeal Crumble

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It’s berry season and you know I’ve been running my cart all over Whole Foods picking up delicious pints of every single berry you can think of. This time of year I’m down to put berries in literally anything. They’re perfect for smoothies, fresh salads, topping yogurt bowls, and of course, making incredible desserts like these blueberry pie bars.

I first made these gluten free blueberry pie bars back in 2019 after the organic blueberries went on sale at the grocery store. Of course, I picked up pints on pints of these delicious berries, and my brain was buzzing about what I should do. Blueberry pie? Too complicated. Blueberry salad? Sound delicious. Blueberry crumble? Maybeeee.

Finally, the winning idea hit: healthier blueberry bars with an oatmeal crumble! Sounds dreamy, right? Just you wait.

These amazing blueberry bars aren’t overly sweet or filling, which makes them perfect for a quick grab and go add to your breakfast or even a snack. The oatmeal crumble is crunchy and full of delicious toasted oatmeal flavor.

Personally, I think they taste like a Nutri-grain bar, which I loved to eat for breakfast growing up.

Ingredients in these easy blueberry pie bars

These healthy blueberry bars use super simple ingredients, come together in just 15 minutes or so, and only take about 30 minutes to bake. To make this recipe, you’ll need:

  • Oat flour: to easily keep the bars gluten free. Learn how to make your own oat flour right at home here!
  • Rolled oats: you’ll need old fashioned rolled oats for that amazing crumble topping. As always, use gluten free rolled oats to keep the bars gluten free, and do not use steel cut oats.
  • Sweetener: we’re using brown sugar to help these bars stay true to flavor and texture. You’ll also need some pure maple syrup to naturally sweeten the filling.
  • Cinnamon: for that true pie flavor in the crust and crumble.
  • Baking staples: remember to use baking soda, salt & vanilla extract. You’ll also want to add a little almond extract for incredible flavor in the crust, crumble & filling.
  • Butter: this helps the crumble clump together and turn a delicious golden color. Use a vegan buttery stick to keep the bars vegan and dairy free!
  • Blueberries: the star of the show in these blueberry pie bars! Feel free to use fresh or frozen in this recipe.
  • Cornstarch: you’ll need a little cornstarch or arrowroot starch to perfectly thicken the blueberry filling.

blueberry bars on a surface with a bite taken out of the middle bar

Simple ingredient swaps

As always I recommend sticking with the recipe as closely as possible to get the best results. There are a few easy swaps you can make in the blueberry pie bars that will stay make them amazing:

  • Swap the flour: if you don’t have oat flour you can easily sub all purpose flour. Reminder: see note below for making your own oat flour at home!
  • Choose your sugar: instead of brown sugar you can also use coconut sugar. Please note that you may not get the best “crumble” in the topping with coconut sugar, and you can also learn how to make your own brown sugar here.
  • For the blueberries: as a reminder, you can use fresh or frozen blueberries in this recipe.

How to make your own oat flour

You can easily make your own gluten free oat flour by simply placing gluten free oats into a blender and blending / pulsing until they’re smooth and resemble a fine flour. This is probably the cheapest option. Check out my tutorial with all of my best tips & tricks. Always measure the oat flour after you blend to ensure that you’re using the proper amount called for in the recipe.

hand pressing the crust into the pan for blueberry pie bars

The best blueberry pie bars in 3 simple step

  • Make the crust & crumble. First, you’ll mix the oats, oat flour, brown sugar, cinnamon, baking soda & salt in a bowl. Then stir in melted vegan butter or regular butter, vanilla extract and almond extract. Press a little more than half of the mixture into an 8 × 8 inch pan lined with parchment paper, then set the rest of the crumble in the fridge for later.
  • Make the filling. make your blueberry pie filling, which is naturally sweetened with pure maple syrup and blueberries. Place a medium pot over medium heat. Add in blueberries, maple syrup, almond extract, cornstarch (or arrowroot) and salt. Use a wooden spoon to press down and break down the blueberries just a bit. Bring to a boil, then reduce the heat and simmer until the filling thickens. Pour over the crust.
  • Assemble & bake. Sprinkle the remaining crumble all over the top of the blueberries and then bake for 30-40 minutes until filling is bubbly and the oatmeal crumble is slightly golden brown. YUM. Cool completely and then cut into bars.

    • blueberry filling being poured on top of crust for blueberry pie bars

    Can I use a different fruit?

    Sure! Because this blueberry pie bar recipe is so versatile, you can easily mix it up with other berries. Be sure to try these amazing pie & crumble bars as well:

    Jazz up your blueberry pie bars

    These gluten free blueberries are, of course, delicious on their own, but I have 2 fun ways for you to jazz up the flavor a bit:

    • Add lemon: mix in zest from 1 lemon for an extra bright, fresh flavor in the filling.
    • Drizzle a glaze: melt a little white chocolate and drizzle it over the bars for an even more decadent treat. You could also do this with a lovely lemon glaze from this cookie recipe! YUM.

    three blueberry pie bars stacked on top one another on a plate

    Storing tips

  • In the fridge: I recommend storing these bars covered in the refrigerator for up to 1 week.
  • In the freezer: yes, these blueberry pie bars are freezer-friendly! Once they’re completely cooled, simply place them in an airtight container and pop them in the freezer for up to 3 months. When you’re ready to enjoy one, just let it thaw a bit in the fridge before eating.

    • More blueberry recipes you’ll love

    Get all of my fresh berry recipes here!

    If you make these blueberry bars, please let me know by leaving a comment and rating the recipe below. I’d love to hear from you and it helps encourage others to make the recipe too! xo.

    Blueberry Pie Bars with Oatmeal Crumble (vegan and gluten free!)

    Perfectly sweet healthy blueberry pie bars topped with a delicious oat crumble. These easy vegan and gluten free blueberry bars taste just like blueberry pie and will be your new favorite treat for spring and summer!

    • For the crust and crumble:

    • 1 ½ cups gluten free oat flour (or sub all purpose flour)

    • 1 cup old-fashioned rolled oats, gluten free if desired

    • ½ cup packed brown sugar (or sub coconut sugar but you may not get the best ‘crumble’)

    • ½ teaspoon ground cinnamon

    • ¼ teaspoon baking soda

    • ¼ teaspoon salt

    • 8 tablespoons butter or vegan buttery stick, melted

    • 1 teaspoon vanilla extract

    • ¼ teaspoon almond extract

    • For the filling:

    • 2 1/2 heaping cups fresh or frozen blueberries

    • 3 tablespoons pure maple syrup

    • 1 tablespoon cornstarch or arrowroot starch

    • ⅛ teaspoon almond extract

    • Optional to make the with a hint of lemon flavor: zest from 1 lemon

    • Pinch of salt

  • Preheat oven to 350 degrees F. Line an 8×8 inch pan with parchment paper and generously spray with nonstick cooking spray. Set aside.

  • Make the base + topping: In a large bowl, use a fork to mix together the oat flour, oats, coconut sugar, cinnamon, baking soda and salt. Add in melted butter, vanilla extract and almond extract and stir until a nice crumble forms and dough begins to clump together.

  • Place 1 3/4 cups of the mixture into the prepared pan and place the remaining mixture into the fridge (the remaining mixture will be used for the topping). Use your hands to evenly press the dough to the bottom of the pan.

  • Next make your blueberry pie filling: place a medium pot over medium heat. Add in blueberries, maple syrup, almond extract, cornstarch (or arrowroot) and salt. Use a wooden spoon to press down and break down the blueberries just a bit.

  • Bring to a boil, then reduce heat and cook for 3-5 more minutes until mixture is thickened up and nicely coats the back of a spoon.

  • Pour mixture over the crust and use a spoon to evenly spread.

  • Take the remaining topping out of the fridge. By now there should be some nice crumbles that have clumped together. Sprinkle the topping over the blueberry filling.

  • Bake for 30 minutes or until filling is bubbly and topping is golden.

  • Allow bars to cool completely on a wire rack before transferring to the fridge to chill. Bars are delicious served at room temperature or straight out of the fridge. Use a sharp knife to cut into 16 bars before serving.

    • To store these blueberry pie bars: the bars are delicious served at room temperature or straight out of the fridge. I recommend storing in the fridge for optimal freshness.

    Nutrition

    Servings: 16 bars

    Serving size: 1 bar (based on 16)

    Calories: 152kcal

    Fat: 5.5g

    Saturated fat: 2.8g

    Carbohydrates: 26.8g

    Fiber: 1.9g

    Sugar: 11.4g

    Protein: 2g

    Recipe by: Monique Volz // Ambitious Kitchen | Photography by Eat Love Eats

    This post was originally published on May 22, 2019, republished on March 10th, 2020, and republished on May 12th, 2022.

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