I can never resist these Blueberry Lemon Crumb Bars: buttery crumbs, bright lemon, and juicy berries in every sweet-tart square. One pan lands somewhere between pie, crumble, and bakery bar, and that’s exactly why I keep coming back.

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I’m obsessed with these Blueberry Lemon Crumb Bars because they hit that sweet-tart spot I never get tired of. I get juicy fresh blueberries, bright fresh lemon juice, and that buttery crumb situation all in one messy, gorgeous square.

But the best part is the contrast: jammy middle, tender bite, crumbly top. No fuss, no fancy bakery attitude.

Just bars I keep sneaking from the pan “to even out the edges.” And yes, I always go back for the corner piece. That little bit of extra crumble?

Mine. These taste like summer decided to show up in dessert form today.

Ingredients

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All-purpose flour gives the bars structure, so they’re crumbly but not totally falling apart.
Granulated sugar sweetens the crust and helps it bake up golden and snacky.
Salt keeps everything from tasting flat, especially with all that sweet blueberry filling.
Baking powder gives the crumb topping a tiny lift, so it’s not dense.
Cold butter makes those buttery clumps everyone secretly picks off first.
Egg helps bind the crust, so you get neat-ish squares instead of blueberry rubble.
Vanilla adds that cozy bakery smell.
Basically, it makes the crust taste warmer.
Fresh blueberries burst into a jammy filling that feels bright, juicy, and summery.
Cornstarch thickens the berries, so you’re not dealing with a runny mess.
Lemon juice and zest wake everything up.
Plus, they balance the sweetness nicely.
Powdered sugar is optional, but it makes them look cute without trying hard.

Ingredient Quantities

2 1/4 cups all purpose flour

3/4 cup granulated sugar

1/4 teaspoon salt

1 teaspoon baking powder

1 cup (2 sticks) cold unsalted butter, cut into pieces

1 large egg

1 teaspoon vanilla extract

4 cups fresh blueberries

1/2 cup granulated sugar for filling

2 tablespoons cornstarch

2 tablespoons fresh lemon juice

1 teaspoon lemon zest

Pinch of salt for filling

Powdered sugar for dusting, optional

How to Make this

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1. Preheat oven to 350 F and lightly grease a 9×13 inch baking pan or line it with parchment paper.

2. In a large bowl whisk together 2 1/4 cups all purpose flour, 3/4 cup granulated sugar, 1/4 teaspoon salt, and 1 teaspoon baking powder.

3. Cut 1 cup cold unsalted butter into the dry ingredients until mixture resembles coarse crumbs.

4. Whisk 1 large egg and 1 teaspoon vanilla extract, then stir into the crumb mixture until it just comes together.

5. Reserve about one third of the dough for the topping, press the remaining dough evenly into the bottom of the prepared pan to form the crust.

6. In another bowl combine 4 cups fresh blueberries, 1/2 cup granulated sugar for filling, 2 tablespoons cornstarch, 2 tablespoons fresh lemon juice, 1 teaspoon lemon zest, and a pinch of salt; toss until berries are evenly coated.

7. Spread the blueberry filling evenly over the prepared crust.

8. Crumble the reserved dough over the berry layer to create the crumb topping.

9. Bake until the topping is golden and the filling is bubbly, about 35 to 45 minutes; cool completely in the pan before slicing.

10. Dust with powdered sugar if desired, then cut into bars and serve.

Equipment Needed

1. Oven and 9×13 inch baking pan (or parchment lined pan)
2. Mixing bowls (one large, one medium)
3. Whisk
4. Pastry cutter or two forks (or food processor) for cutting cold butter into flour
5. Measuring cups and spoons
6. Rubber spatula or wooden spoon
7. Microplane or zester and a small knife for lemon
8. Measuring cup or small bowl for tossing blueberries
9. Cooling rack and sifter or fine mesh sieve for powdered sugar dusting

FAQ

What pan size should I use and how long do I bake the bars?

Use a 9×13 inch baking pan lined with parchment for easy removal. Bake at 350 F for 40 to 50 minutes until the top is golden and the filling is bubbling around the edges.

Can I use frozen blueberries instead of fresh?

Yes. Do not thaw them. Toss frozen berries with the sugar and cornstarch and add 5 to 10 extra minutes to the baking time so the filling has time to thicken.

What can I substitute for cornstarch if I do not have any?

Use 3 tablespoons of all purpose flour as a thickener, or 2 teaspoons of instant tapioca powder for a clearer, glossy filling. Increase flour slightly may make filling a bit denser.

Can I make the crust and crumbs ahead of time?

Yes. Prepare the crumb mixture and refrigerate up to 2 days or freeze up to 1 month. If frozen, grate or cut chilled butter into the flour mixture before pressing into the pan.

How should I store the baked bars and how long do they keep?

Cool completely, then store in an airtight container in the refrigerator for up to 5 days. Bars can be frozen for up to 2 months; thaw overnight in the fridge.

How do I get distinct crumbs and a sturdy crust without overworking the dough?

Keep the butter very cold and work quickly. Use a pastry cutter, two forks, or pulse briefly in a food processor until pea size crumbs form. Press half firmly for the base and reserve the rest loosely for the topping.

Blueberry Lemon Crumb Bars Recipe Substitutions and Variations

All purpose flour
- Pastry flour for a more tender crumb (use 1:1)
- Whole wheat pastry flour for nuttier flavor (substitute up to 50 to 100 percent)
- Gluten free 1-to-1 baking blend (use 1:1, may need extra binding)
Unsalted butter
- Cold vegan butter or plant-based stick margarine (use 1:1)
- Vegetable shortening for a very tender, less flavorful crumb (use 1:1)
- Chilled coconut oil solidified in the fridge for subtle coconut notes (use 1:1)
Fresh blueberries
- Frozen blueberries, thawed and drained (toss with a little cornstarch to absorb extra juice)
- Raspberries or blackberries for brighter tartness (use equal volume)
- Blueberry jam plus fresh berries for extra jammy filling (reduce added sugar)
Cornstarch
- Arrowroot powder (use 1:1, clear finish)
- Tapioca starch (use 1:1, slightly chewier set)
- All purpose flour (use 2:1, may yield less glossy filling)

Pro Tips

1. Keep the butter very cold and work quickly when cutting it into the flour; those chilly pea-sized bits create flaky crumbs and a tender crust.

2. Toss the blueberries with the cornstarch, sugar, lemon juice, and zest and let them sit for 10 minutes before spreading. That short rest helps the fruit release some juice and the cornstarch start thickening so the filling is saucy but not runny.

3. Press the crust evenly and firmly into the pan so it holds together when slicing. Use the bottom of a measuring cup for a smooth, compact layer.

4. If the topping browns too fast while the filling is still bubbling, tent loosely with foil for the last 10 to 15 minutes of baking to prevent overbrowning.

5. Cool completely in the pan before cutting. Chilling for an hour makes cleaner slices and helps the filling set, giving you neat bars instead of a gooey mess.

Blueberry Lemon Crumb Bars Recipe

Recipe by Sammy Hunter

0.0 from 0 votes

Servings

servings

Calories

503

kcal

Equipment: 1. Oven and 9×13 inch baking pan (or parchment lined pan)
2. Mixing bowls (one large, one medium)
3. Whisk
4. Pastry cutter or two forks (or food processor) for cutting cold butter into flour
5. Measuring cups and spoons
6. Rubber spatula or wooden spoon
7. Microplane or zester and a small knife for lemon
8. Measuring cup or small bowl for tossing blueberries
9. Cooling rack and sifter or fine mesh sieve for powdered sugar dusting

Ingredients

2 1/4 cups all purpose flour
3/4 cup granulated sugar
1/4 teaspoon salt
1 teaspoon baking powder
1 cup (2 sticks) cold unsalted butter, cut into pieces
1 large egg
1 teaspoon vanilla extract
4 cups fresh blueberries
1/2 cup granulated sugar for filling
2 tablespoons cornstarch
2 tablespoons fresh lemon juice
1 teaspoon lemon zest
Pinch of salt for filling
Powdered sugar for dusting, optional

Directions

Preheat oven to 350 F and lightly grease a 9×13 inch baking pan or line it with parchment paper.
In a large bowl whisk together 2 1/4 cups all purpose flour, 3/4 cup granulated sugar, 1/4 teaspoon salt, and 1 teaspoon baking powder.
Cut 1 cup cold unsalted butter into the dry ingredients until mixture resembles coarse crumbs.
Whisk 1 large egg and 1 teaspoon vanilla extract, then stir into the crumb mixture until it just comes together.
Reserve about one third of the dough for the topping, press the remaining dough evenly into the bottom of the prepared pan to form the crust.
In another bowl combine 4 cups fresh blueberries, 1/2 cup granulated sugar for filling, 2 tablespoons cornstarch, 2 tablespoons fresh lemon juice, 1 teaspoon lemon zest, and a pinch of salt; toss until berries are evenly coated.
Spread the blueberry filling evenly over the prepared crust.
Crumble the reserved dough over the berry layer to create the crumb topping.
Bake until the topping is golden and the filling is bubbly, about 35 to 45 minutes; cool completely in the pan before slicing.
Dust with powdered sugar if desired, then cut into bars and serve.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.