These blueberry lemon crumble bars layer jammy fresh blueberries between a buttery, sandy crumble that gets crisp on top and stays tender underneath. The lemon zest and juice cut through the sweetness just enough to keep you reaching for another piece.
The same crumble mixture forms both the base and the topping, which means fewer bowls! The base gets pressed down firmly so it holds the juicy filling, then the rest gets tossed with brown sugar and scattered on top for texture contrast. When the bars come out of the oven, the blueberries are bubbling and the crumble is golden and crisp at the edges.
I wanted something that felt less advance than a blueberry pie! These work for breakfast with coffee or dessert after dinner. 🙂
Why you’ll love this recipe
Same dough, two textures – the crumble mixture pulls double duty as both a sturdy base and a crisp, sandy topping without any extra work.
Lemon keeps it balanced – fresh zest and juice brighten the filling so the bars taste fruity and tangy, not candy-sweet.
Small batch, no mixer – an 8×8 pan means you’re not committed to feeding a crowd, and everything comes together with a bowl and a wooden spoon.
Ingredients
- Fresh blueberries
- Cornstarch
- Lemon zest
- Freshly squeezed lemon juice
- Granulated sugar
- All-purpose flour
- Baking powder
- Unsalted butter, room temperature
- Egg yolk
- Brown sugar
Equipment
- 8×8 inch baking dish
- Parchment paper
- Zester or microplane
Tips for making Blueberry Lemon Crumble Bars
- Room temperature butter matters – it should be soft enough to press a finger into but not greasy or melted, or the crumble won’t hold its texture. Pull it out of the fridge about an hour before you start.
- Press the base firmly – use the bottom of a measuring cup or a flat glass to compact the bottom layer so it doesn’t crumble apart when you slice the bars later.
- Don’t press the top crumble – scatter it over the blueberries and leave it loose so it bakes up crisp and sandy, not dense.
- Let them cool completely – these are runny and soft when hot, but they firm up as they cool. If you cut them warm, you’ll get a tasty mess instead of clean squares.
- Add extra cornstarch for juicy berries – if your blueberries are particularly plump and wet, toss in an extra half teaspoon of cornstarch to keep the filling from turning soupy.
Make sure to tag me @theflournook on social media and leave a review below if you make these blueberry lemon crumble bars. To pin this recipe and save it for later, you can use the button on the recipe card, the buttons above or below this post, or on any of the photos above.
Happy baking!
Blueberry Crumble Bars
- Total Time: 1 hour 5 minutes
- Yield: 16 bars 1x
Description
Blueberry lemon crumble bars layer jammy fresh blueberries between a buttery crumble that’s crisp on top and tender underneath. Bright lemon zest and juice keep the filling balanced and fruity. Easy to make in an 8×8 pan with no mixer needed.
Ingredients
Blueberry Filling
- 2 cups (300 grams) fresh blueberries
- 2 teaspoons (6 grams) cornstarch
- 1 teaspoon (2 grams) lemon zest
- 1 tablespoon (15 milliliters) freshly squeezed lemon juice
- 1/4 cup (50 grams) granulated sugar
Crumble
- 1 1/4 cups (150 grams) all-purpose flour
- 1/2 cup (100 grams) granulated sugar
- 1/2 teaspoon (2 grams) baking powder
- 1/4 cup (57 grams) unsalted butter, room temperature
- 1 large egg yolk
- 1 tablespoon (13 grams) brown sugar
- 1 tablespoon (12 grams) granulated sugar
Instructions
-
Preheat your oven to 375°F (190°C). Line an 8×8 inch baking dish with parchment paper.
-
Toss the blueberries, cornstarch, lemon zest, lemon juice, and sugar together in a medium bowl. Set aside.
-
Beat the butter, flour, sugar, baking powder, and egg yolk together in a large bowl until the mixture looks like coarse crumbs.
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Take two-thirds of the crumble mixture and press it firmly into the bottom of your prepared baking dish to form an even layer.
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Pour the blueberry mixture over the pressed crumble base.
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Add the brown sugar and remaining granulated sugar to the leftover crumble mixture and toss to combine. Sprinkle this over the blueberries.
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Bake for 45 minutes until the blueberries are bubbling and the crumble topping is golden and crisp.
-
Let the bars cool completely in the pan before cutting into squares, they’ll be quite runny when hot but will firm up as they cool.
Notes
Don’t skip the full cooling time, these really do need to set up completely or you’ll end up with a delicious mess.
If your blueberries are particularly juicy, add an extra half teaspoon of cornstarch to the filling.
The room temperature butter is key here. it needs to be soft enough to work into crumbs but not melted, so pull it out about an hour before you start.
- Prep Time: 20 mins
- Cook Time: 45 mins
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