Easy Old Fashioned Blueberry Crumb Bars

Name: Blueberry Crumb Bars
Prep time: 15 min
Cook time: 45 min
Total time: 60 min
Ingredients: 3 cups flour; 1/2 cup brown sugar; 1/2 cup white sugar; 1 teaspoon baking powder; 1 teaspoon salt; 1/4 teaspoon ground cinnamon; 1 cup butter; 1 egg; 4 cups fresh blueberries; 1/2 cup white sugar; 3 teaspoons cornstarch

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Jump to Recipe

Blueberry crumb bars are an easy dessert bar made with a buttery, old-fashioned crumb crust and a sweet, fresh blueberry filling. They’re a classic summer blueberry dessert, perfect for using up a fresh blueberry harvest or a trip to the farmers market.

Unlike a pie, there is no fussy crust to roll out. These blueberry crumble bars slice into neat squares, making them an easy dessert to pack for a potluck, picnic, or lunchbox treat.

A Quick Look At The Recipe

Recipe Name: Blueberry Crumb Bars
Cook Time: 45 minutes (plus cooling time)
Servings: 24 small bars (9×13 pan)
Main Ingredients: Flour, butter, fresh blueberries
Dietary Info: Vegetarian
Difficulty Level: Easy

Blueberry crumb bars stacked on a white plate with fresh blueberries in front.

These are one of my favorite easy blueberry desserts to make once berry season hits. The buttery crumb crust and sweet blueberry filling are just the perfect combination for a sweet treat. It’s right up there with my other must-make desserts blueberry crisp and peach blueberry crisp.

If you’ve got a bowl of fresh blueberries you don’t know what to do with, this is exactly the kind of easy recipe that turns them into a treat your family will love.

Why You’ll Love These
Blueberry Crumb Bars

Easy to make: No fancy technique required, just a simple crumb crust and a fresh blueberry filling.
Old-fashioned flavor: A hint of cinnamon and brown sugar gives this crumb crust that classic, homemade taste.
Perfect for a crowd: A 9×13 pan makes plenty of bars for a potluck, picnic, or a busy household.
Great for using up fresh blueberries: One of the best summer blueberry desserts for a big berry haul.

Ingredients

Crust

3 cups flour
½ cup brown sugar
½ cup white sugar
1 teaspoon baking powder
1 teaspoon salt
¼ teaspoon ground cinnamon
1 cup butter
1 egg

Filling

4 cups fresh blueberries
½ cup white sugar
3 teaspoons cornstarch

How To Make Blueberry Crumb Bars

Prep The Pan

Preheat your oven to 375°F and grease a 9×13 pan and set it aside.

owl of crumb topping mixture for blueberry crumb bars on a marble counter with a blue and white checkered towel behind it.

Make The Crust

In a medium mixing bowl, combine the flour, 1/2 cup brown sugar, 1/2 cup white sugar, and baking powder. Mix in the salt and cinnamon.

Cut In The Butter

Add the butter and egg, then cut in with a pastry cutter until the dough is a crumbly texture.

Crumb mixture pressed into the bottom of a glass baking dish to make the crust for blueberry crumb bars.

Blueberries mixed with sugar and cornstarch in a white bowl for the filling layer of blueberry crumb bars.

Press The Base

Add half of the dough to your prepared pan and pat it down to evenly cover the bottom.

Make The Filling

In a separate bowl, mix the ½ cup of sugar and cornstarch together, then gently fold in the blueberries.

Blueberry filling spread over the crumb crust in a glass baking dish, with extra crumb topping waiting in a mixing bowl.

Unbaked blueberry crumb bars in a glass baking dish with a thick crumb topping spread over the blueberry filling.

Layer And Top

Sprinkle the blueberry mixture evenly over the crust, then crumble the remaining dough over top of the blueberries.

Bake

Bake for 45 minutes, or until the top is slightly browned.

Cool

Let the bars cool completely before cutting into squares.

Freshly baked blueberry crumb bars in a glass baking dish with a golden crumble topping and blueberry filling peeking through.

Recipe Notes & Tips

Cooling is key: Let these cool completely before cutting, so the bars hold their shape better.
For the cleanest cut: Chill the pan in the fridge for a few hours, or even overnight, before slicing into bars.
Don’t overmix the crust: A crumbly texture is exactly what you want, overworking the dough will make it tough instead of tender.
Storage: Store in an airtight container in the fridge for up to a week.

Blueberry crumb bar on a white plate with fresh blueberries beside it and more bars stacked in the background.

Substitutions

Fresh blueberries: Frozen blueberries can also be used, though you may need a little extra cornstarch to account for the extra moisture.
Cinnamon: Leave it out for a more classic buttery crust, or add a touch more for extra warmth.

Variations

Lemon blueberry bars: Add the zest of one lemon to the filling for a bright, citrusy twist.
Mixed berry bars: Swap out a cup or two of the blueberries for raspberries or blackberries.
Extra crumbly: Add ½ cup of rolled oats to the crumb topping for a heartier, streusel-like texture.

Close up of a blueberry crumb bar with a golden topping and thick blueberry filling on a white plate.

FAQ’s

Let the bars cool completely, then chill them in the fridge for a few hours or overnight before cutting for the cleanest slices.

Yes, frozen blueberries work well, though you may want to add a bit more cornstarch since frozen berries release more liquid as they bake.

Stored in an airtight container in the fridge, they’ll keep for up to a week.

Yes, once fully cooled, these freeze well. Wrap individual bars tightly and freeze for up to 3 months.

Blueberry Crumb Bars

This easy blueberry crumb bar recipe is a classic summer favorite. A buttery, old-fashioned crumb crust surrounds a sweet, fresh blueberry filling, perfect for using up a berry haul!

Prep Time 15

Cook Time 45

Total Time 1

Serving Size squares

Ingredients

Crust

3 cups flour
1/2 cup brown sugar
1/2 cup white sugar
1 teaspoon baking powder
1 teaspoon salt
1/4 teaspoon ground cinnamon
1 cup butter
1 egg

Filling

4 cups fresh blueberries
1/2 cup white sugar
3 teaspoons cornstarch

Instructions

Preheat the oven to 375F and grease a 9×13 pan.
Combine flour, 1/2 cup brown sugar, 1/2 cup white sugar, and baking powder in a medium-sized mixing bowl. Mix in salt and cinnamon.
Add the butter and egg, cutting in with a pastry cutter. The dough will be a crumbly texture.
Add half the dough to your baking pan and pat down to cover the bottom.
In a separate bowl, mix 1/2 cup of sugar and the cornstarch together. Then gently mix in the blueberries.
Sprinkle the blueberry mixture over the crust.
Then crumble the rest of the dough over top of the blueberries.
Bake for 45 minutes or until the top is slightly brown.
Let cool completely before cutting into squares.

Notes

Tip: If you cool in the fridge for a few hours to overnight, they should be easy to cut.

Nutrition

These values are from a nutritional database and automatically calculated, and should only be used as an approximation.

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Kim

Kim Mills is a homeschooling mom of 6 and lives on an urban homestead in Ontario, Canada. Blogging at Homestead Acres she enjoys sharing tips to help you save money, grow and preserve your own food.