Blueberry Crumb Bars
intro
Buttery, crumbly shortbread bars layered with bright, tart-sweet fresh blueberry filling, an easy, portable baked treat ideal for casual summer sharing.
Ingredients
Steps
Preheat Oven and Line Pan
Preheat your oven to 375°F (190°C) with a rack positioned in the middle. Line a 9x9 inch (23cm) square metal baking pan with parchment paper, leaving a 2-inch (5cm) overhang on two opposite sides to act as handles for easy removal later.
Whisk Dry Crumb Ingredients
In a large mixing bowl, whisk together 2 ¼ cups (270g) all-purpose flour, ½ cup (100g) granulated sugar, ¼ cup (50g) packed light brown sugar, 1 teaspoon lemon zest, ½ teaspoon baking powder, and ¼ teaspoon fine sea salt until evenly combined. Add the cold cubed unsalted butter, and use your fingertips or a pastry cutter to work the butter into the dry mix until it forms coarse, pea-sized crumbs with some larger walnut-sized clumps. Measure out 1 ½ cups of the crumb mixture and set it aside in a small bowl for the topping.
Prepare Blueberry Filling
In a medium mixing bowl, combine the 3 cups (450g) rinsed, thoroughly patted-dry blueberries, remaining 2 tablespoons (25g) granulated sugar, 2 tablespoons cornstarch, and 1 tablespoon fresh lemon juice. Toss gently with a rubber spatula until every blueberry is evenly coated, and no dry, white cornstarch clumps remain at the bottom of the bowl.
Press Crumb Base Layer
Pour the remaining unreserved crumb mixture into the prepared parchment-lined pan. Use the flat bottom of a dry measuring cup to press the crumbs firmly into a tight, even, gap-free layer across the entire bottom of the pan, taking care to press the crumbs right up to the pan edges.
Spread Filling and Add Topping
Spoon the coated blueberry mixture over the pressed crumb base, and spread it into a single even layer that reaches all pan edges. Sprinkle the reserved 1 ½ cups of crumb mixture loosely and evenly over the top of the blueberries, leaving small gaps so patches of bright blue fruit peek through; do not press the topping down into the filling.
Bake Bars Until Golden Bubbly
Place the pan on the preheated middle oven rack, and bake for 35 to 40 minutes, until the top crumb is deep golden brown and the blueberry filling is bubbling vigorously around the pan edges. Once baked, transfer the pan to a wire cooling rack, and let the bars cool completely for 1 full hour at room temperature before lifting them out via the parchment overhang and slicing into 9 equal 3-inch squares.
Tips
2.Wait the full 60 minutes for bars to cool before slicing: cutting warm bars will cause the unset, runny blueberry filling to ooze out, leading to crumbly, messy slices.
3.If using frozen blueberries, do not thaw them before tossing with cornstarch and lemon juice; adding frozen berries directly prevents the filling from turning mushy and staining the crumb layers dark purple.
OMG these blueberry crumb bars are a GAME CHANGER! I brought them to my neighborhood potluck last weekend and every single person asked for the recipe. The crumb topping is so buttery and the blueberry filling is perfectly tart-sweet, not cloying at all. My 3 kids even asked for seconds before they finished their first serving! Total win for easy weeknight baking too.
Super easy recipe, but my crumb topping came out way too dry and crumbly? Like it wouldn’t hold together when I pressed the base into the pan, and the top crumbs just kind of slid off the filling when I cut into bars after cooling. Did I mismeasure the butter? I used salted butter instead of unsalted if that makes a difference?
These are PERFECT for my weekly meal prep! I made a batch on Sunday, cut them into squares, and stashed them in the fridge for quick breakfasts and afternoon snacks all week. They hold up so well, even after 5 days in an airtight container. 10/10 will be making these every other week while blueberries are in season!
I’ve been making my own blueberry bar recipe for 40 years and decided to give this one a shot to switch things up. Let me tell you, the hint of lemon zest in the filling? *Chef’s kiss.* My grandkids went absolutely wild for them, said they’re better than mine (rude, but fair, lol). I added a tiny drizzle of lemon glaze on top after they cooled, highly recommend that tweak!
SO good! I swapped half the all purpose flour for whole wheat pastry flour to make them a little more fiber-heavy, and used coconut sugar instead of granulated, and they still turned out absolute chef’s kiss. You can’t even tell I made healthier swaps, my roommate ate three in one sitting. Easy enough even for someone who bakes like once a month, like me.
Wait, how thick should I press the base crust? I’m always paranoid I’m pressing it too thin or too thick and ruining the whole pan. This is my first time making crumb bars ever so I’m over here overthinking every step 😂
Made these for my office picnic last week and they were gone in 10 minutes flat. People were hovering over the dessert table waiting for me to set the pan down, no joke. Only note: I wish I’d made a double batch! Will be doubling next time for sure.
I used fresh blueberries I picked myself at a local u-pick farm last weekend and these bars tasted like straight summer. The crumb is buttery, oaty, not too sweet, lets the blueberry flavor really shine. I even ate a piece for breakfast with a dollop of Greek yogurt on top, 10/10 breakfast hack.
Loved how straightforward this recipe is! No fancy equipment needed, I didn’t even pull out my stand mixer — just a bowl and a pastry cutter, done in 15 minutes of prep before popping it in the oven. Perfect for when I want a homemade treat without a million steps or dirty dishes.
The texture of these bars is perfect! Not too gooey, not too dry, the crumb topping gets those nice little crispy edges around the pan that are my absolute favorite part. I added a tiny pinch of cinnamon to the crumb mixture and it paired so well with the blueberries, I’ll never make them without it again.
Full transparency: I burn 90% of the baked goods I try to make. I followed this recipe exactly, set a timer, and these came out perfectly golden, no burnt edges, no raw middle! I’m actually so proud of myself, and they taste incredible. Even my partner who ‘doesn’t like fruit desserts’ had two pieces. Win!
These were really tasty, but I found the filling a little runnier than I expected even after letting them cool for the full hour like the recipe says. Next time I’ll add an extra half tablespoon of cornstarch to the blueberry mixture to help it set up firmer, otherwise flavor was 10/10!