Lemon Blueberry Crumble Bars

Looking for a recipe for unforgettable lemon blueberry bars topped with a rich, buttery oat crumble? Look no further! These are the Lemon Blueberry Crumble Bars of your dreams.

Foolproof and simple, these blueberry bars with a hint of lemon are a HUGE hit whenever I serve them. Think of them as a mini slice of blueberry pie with a crumb crust...ice cream optional. Ready to give them a try? Keep reading for step-by-step instructions for making these Lemon Blueberry Crumble Bars at home.

Why This Recipe Works

• The crust bakes in the oven at a low temperature before being topped with the blueberry filling, which helps it from becoming soggy.
• The perfect combination of blueberries, lemon zest, lemon juice and sugar create a very berry filling with just the right lemon-y notes.
• The crumble topping is delightfully craggy in texture and buttery in flavor making a wonderful foil for the blueberry filling.

Ingredients

For The Crust:

For The Crumble:

For The Filling:

• This recipe calls for a combination of all purpose flour and rye flour, both in the crust and the crumble. I love baking with rye flour, as it brings a delicious earthy flavor to breads and other baked goods. BUT, you certainly can just substitute an equal amount of additional all purpose flour or some other whole grain flour such as whole wheat or spelt if you don't want to seek out the rye.
• You will find dark brown sugar in both the crust and crumble. It brings a deep caramel-y flavor to the finished product and is a very nice choice here. BUT if you only have light brown sugar, that will be fine here too.
• Including both lemon juice and freshly grated lemon zest to the blueberry filling really dials up the lemon flavor and is such a nice compliment to the sweet berries.

Equipment

• A food processor
• Parchment paper
• 9x9 baking pan
• Small offset spatula (optional but really helpful)

How to Make This Recipe

• Begin by preheating the oven to 275 degrees. buttering the bottom and sides of a 9x9 baking pan and cutting a piece of parchment paper to fit inside the pan with enough length to hang over the sides. And then take the extra step of buttering the bottom and sides of the parchment (just a couple of inches up the sides is fine). Not only will this help ensure that your bars won't stick, it creates a sling so that you can take the bars out of the pan before cutting them if you so choose. Set aside.

• Combine the ingredients for the crust (except the butter and vanilla) in a food processor. Pulse a few times to combine.
• Drizzle the melted butter and vanilla over the top and process until the mixture resembles wet sand.
• Transfer the crust mixture to the prepared pan. Press the crust evenly into the bottom of the pan using your fingers. Once it is relatively even, grab a metal measuring cup and press/slide it over the top of the crust to pack it firmly. Transfer the crust to the freezer for 20 minutes or so why you prepare the crumble topping.

• Grab the empty (no need to wash) work bowl for the food processor. Add the ingredients for the crumble except for the butter. Pulse a few times or until the oats have broken down into smaller pieces. Transfer to a medium bowl and drizzle the butter over the top. Stir together with a fork until the mixture is evenly moistened. Set aside.

• Pop the crust in the oven for 50 minutes. In the meantime, make the filling: Combine all of the ingredients in a saucepan and place over medium heat. Stir occasionally until the mixture starts to bubble. Reduce the heat to medium low and continue to cook until thickened, about 3 minutes. Set aside to cool slightly.

• Once the crust comes out of the oven, increase the oven temperature to 350 degrees. Top the warm crust with the blueberry filling. Squeeze some of the crumble mixture together in your hand.  Tear off irregular-sized pieces of the crumble and scatter it in an even layer over the top of the blueberry filling.  Crumble pieces should be ¾ inch in diameter or smaller. Repeat with remaining crumble. Press gently on the top of the crumble with the back of a spatula to create an even layer and help the crumble stick together.

• Bake for about 50 minutes or until the crumble topping is golden brown. Transfer the pan to a wire rack to cool slightly before placing in the fridge for a few hours to chill bars before slicing. 
• Before serving, run a small knife along the inside edge of the pan to loosen any blueberries that may be stuck to the sides.  If you have chilled the bars in the fridge, gently lift the parchment paper sling and remove bars in one piece from pan. Cut into squares and serve.  If you have simply let the bars cool to room temperature without chilling, slice the bars in the pan into squares and serve.

Expert Tips

• Butter the bottom and sides of a 9 x 9 inch square baking pan and cut a piece of parchment paper to fit inside the pan with enough length to hang over the sides. And then take the extra step of buttering the bottom and sides of the parchment (just a couple of inches up the sides is fine). Not only will this help ensure that your bars won't stick, it creates a sling so that you can take the bars out of the pan before cutting them if you so choose. If you decide to take them out in one big piece using the sling, you must chill the bars for several hours in the fridge beforehand to make sure they are firm enough and won't fall apart.
• After you pat the crust into the pan, press/slide the bottom of a metal measuring cup over the crust to even it out and ensure that it is packed tightly.
• Freeze the crust briefly and bake prior to adding the filling. This creates a firm, shortbread-like base for your bars and keeps them from getting soggy.
• Once you have added the crumble topping to the pan, gently press down on it with the back of a spatula. This helps create an even bar and keeps the crumble from falling off once you are ready to cut and serve the bars.
• Do not skimp on the cooling/chilling time! If you try to cut into these while they are still warm, you will end up with something more like blueberry cobbler. The crust needs time to cool and set up. At the very least, wait until they have cooled to room temperature. Better yet, chill the bars for several hours in the fridge before slicing. That way you can use the parchment sling to easily remove them from the pan and they are delicious chilled.
• All of the components can be made in advance. Keep the crust in the freezer and the filling and crumble in the fridge for up to 24 hours before beginning the baking process.

FAQs

Related Recipes

Looking for more delicious blueberry recipes? I've got you covered:

Lemon Blueberry Crumble Bars

Delicious, buttery crumble bars with a lemon blueberry filling.

5 from 1 vote

Print Pin Rate

Course: Dessert, Fika, Snack

Cuisine: Nordic, Scandinavian

Keyword: blueberry bars, blueberry crumble recipe, crumble bar recipe, lemon blueberry bars

Prep Time: 15 minutes

Cook Time: 1 hour 45 minutes

Freeze: 20 minutes

Total Time: 2 hours 20 minutes

Servings: 16 bars

Calories: 231kcal

Author: Kristi

Ingredients

For the Crust:

• ▢ ½ cup dark rye flour (optional, see note below) I like the Bob’s Red Mill brand
• ▢ 1 cup all purpose flour
• ▢ ⅓ cup packed dark brown sugar
• ▢ ½ teaspoon coarse salt
• ▢ ½ cup unsalted butter melted and cooled
• ▢ 1 teaspoon vanilla extract

For the Crumble:

• ▢ 1 cup old-fashioned rolled oats
• ▢ 3 tablespoons packed dark brown sugar
• ▢ ¼ cup + 2 tablespoons rye flour (optional, see note below)
• ▢ ¼ cup all purpose flour
• ▢ 3 tablespoons granulated sugar
• ▢ 1 teaspoon coarse salt
• ▢ 6 tablespoons unsalted butter melted and cooled

For the Filling:

• ▢ 3 cups blueberries preferably wild (frozen is fine)
• ▢ ⅓ cup granulated sugar
• ▢ 1 tablespoon lemon juice
• ▢ Finely grated zest from 1 lemon
• ▢ 2 tablespoons cornstarch
• ▢ Pinch of coarse salt

US Customary - Metric

Instructions

• Make the crust:  Preheat oven to 275 degrees.  Butter a 9 x 9 inch cake pan. Cut a piece of parchment paper to fit the inside of the pan, with enough overhang so that the parchment covers the bottom and comes up and over the sides by a couple of inches creating a sling.  Place the parchment inside the pan. Butter the bottom and up the sides of the parchment just a couple of inches.
• Combine flours, brown sugar and salt together in a work bowl of a food processor. Process until combined.  Add melted butter and vanilla. Pulse until fully combined and the texture of wet sand.
• Transfer dough to prepared pan. Set empty work bowl aside to use for the crumble (no need to rinse).   Press dough evenly into the bottom of the prepared pan, using the bottom of a metal measuring cup to smooth it out and press it flat.  Place crust in the freezer while you make the crumble (about 20 minutes).
• Meanwhile, make the crumble:  Combine all ingredients except the butter in the work bowl of a food processor.  Pulse until combined and oats are slightly broken up, approximately 5-7 pulses. Transfer mixture to a bowl and add melted butter.  Stir with a fork to combine. Set aside.
• Place the frozen crust in the oven.  Bake for 50 minutes or until light brown and slightly firm to the touch.
• Meanwhile, make the filling:  Combine all ingredients in a medium saucepan.  Stir over medium low heat until berries begin to give up their juice, about 2-3 minutes.  Increase heat to medium and cook, stirring constantly, until the mixture has become jam-like in texture, about 2 more minutes.  Remove from heat. Set aside to cool.
• When the crust comes out of the oven, increase the oven temperature to 350 degrees.   Spread the blueberry filling evenly over the top of the crust (a small offset spatula works really well here), taking care not to touch the hot pan.
• Squeeze some of the crumble mixture together in your hand.  Tear off irregular-sized pieces of the crumble and scatter it in an even layer over the top of the blueberry filling.  Crumble pieces should be ¾ inch in diameter or smaller. Repeat with remaining crumble. Press gently on the top of the crumble with the back of a spatula to create an even layer and help the crumble stick together.
• Return the pan to the oven and bake for 50 minutes or until crumble topping is crisp and golden brown.  Transfer pan to a wire rack to cool slightly before placing in the fridge for a few hours to chill bars before slicing.  
• Before serving, run a small knife along the inside edge of the pan to loosen any blueberries that may be stuck to the sides.  If you have chilled the bars in the fridge, gently lift the parchment paper sling and remove bars in one piece from pan. Cut into squares and serve.  If you have simply let the bars cool to room temperature without chilling, slice the bars in the pan into squares and serve.

Notes

• This recipe calls for a combination of all purpose flour and rye flour, both in the crust and the crumble. I love baking with rye flour, as it brings a delicious earthy flavor to breads and other baked goods. BUT, you certainly can just substitute an equal amount of additional all purpose flour or some other whole grain flour such as whole wheat or spelt if you don't want to seek out the rye.
• Do not skimp on the cooling/chilling time! If you try to cut into these while they are still warm, you will end up with something more like blueberry cobbler. The crust needs time to cool and set up. At the very least, wait until they have cooled to room temperature. Better yet, chill the bars for several hours in the fridge before slicing. That way you can use the parchment sling to easily remove them from the pan and they are delicious chilled.
• All of the components can be made in advance. Keep the crust in the freezer and the filling and crumble in the fridge for up to 24 hours before beginning the baking process.
• Store the bars tightly wrapped in the refrigerator for 2 to 3 days.  Freeze for longer storage.

 

Adapted from Good to the Grain by Kim Boyce and Scandinavian Cooking by Beatrice Ojakangas

 

Nutrition

Calories: 231kcal | Carbohydrates: 33g | Protein: 3g | Fat: 11g | Saturated Fat: 6g | Cholesterol: 27mg | Sodium: 222mg | Potassium: 75mg | Fiber: 2g | Sugar: 16g | Vitamin A: 323IU | Vitamin C: 4mg | Calcium: 15mg | Iron: 1mg

If you loved this recipe, give it a star review! Also, snap a picture of your Lemon Blueberry Crumble Bars and share it with me on Instagram using the hashtag #truenorthkitchen and tagging me @true_north_kitchen.