Easy Blueberry Crumble Bars

Sharing is caring!

Last updated on August 25th, 2022

These easy blueberry crumble bars have a buttery oatmeal base that also doubles as the delicious crumb topping. They use fresh blueberries and can easily be made ahead of time! A delicious recipe that everyone will be asking you for!

blueberry crumble bars stacked on top of each other with more bars in the background

My mom is an excellent baker and I’ve always looked forward to her creations. Our family get-togethers are usually loaded with an excess of food and dessert options, but I tend to gravitate towards my mom’s every single time.

But earlier this summer I made these Blueberry Crumb Bars and I didn’t even care what anyone else brought. Once I had the 1st bite, I could have thrown my Mom’s dish straight to the trash and it would have been a smart decision.

Because these bars were EVERYTHING.

Luckily, she agreed with me. She literally sat there repeating on a loop “These are so good, Nat”, “I really like these a lot, Nat”, “Are you giving me any to take home, Nat?”

They have a soft buttery crust, a blueberry filling with just the slightest bit of sweetness and then are topped with the oatmeal crumb that brings the whole thing together.

And they hold together soooo well. Some crumb bars are so soft that they’re falling out of your hand, and you’re cursing as it hits the ground while the dog makes a beeline for it. But not these little gems. They’re solid while still being tender. It’s an amazing combination.

blueberry crumb bars stacked on top of each other

How to Make Blueberry Crumb Bars

Oatmeal Crumb Crust

Start by making your crumb crust which is super easy because you can mix all your ingredients together at once. No separate bowls and no separate stages!

I start by taking a large mixing bowl, and adding 1.5 cups (3 sticks) of butter to it. Make sure it’s butter and not margarine! I promise, it makes a difference. Melt the butter in the microwave.

Once it’s melted, add:

3 cups of rolled oats
3 cups of all-purpose flour
2 cups of brown sugar
1 teaspoon baking powder
1/2 teaspoon salt

Mix everything together really well and then press 2/3 of the mixture into the bottom of a 9×13 pan. Press it down really well and bake at 350 degrees for 10 minutes.

Blueberry Filling Recipe

blueberries and cornstarch in a saucepan

While your crust is baking, you can get to work on your fresh blueberry filling!

In a medium saucepan, add:

2 cups Fresh Blueberries
2 tablespoons cornstarch
1/2 cup sugar
2 tablespoons lemon juice

Bring everything to a boil, making sure you are stirring the whole time. If you don’t stir, it will burn and that would make me cry. Keep on stirring it until the mixture is thickened, about 2-3 minutes.

Spread the blueberry mixture over the baked crust. Then sprinkle with all of the reserved crumbs.

Bake at 350 degrees for about 25 minutes or until the topping is just starting to turn golden brown.

metal 13x9 pan with uncut blueberry crumb bars

Now comes the hardest part, let them sit! You could eat them right away if you have to, but they won’t be able to hold their shape yet. Not that there’s anything wrong with eating a pile of blueberry crumb with a spoon. It will be just like a good ole fashioned blueberry crisp recipe!

a metal pan with blueberry crumb bars with pieces cut away

But these are bars, and to get to that point, you need to let them chill for a bit. I stick them in the fridge for a couple hours so they set up nice and firm. And actually, just because I prefer them cold. You can definitely store them at room temperature, but try one chilled and tell me you don’t like that better!

blueberry crumble bars on a piece of slate with a dish towel in the background

If you’re looking for other ways to use up your blueberries, these are some of my favorites:

Blueberry Upside Down Bread– with a lemon glaze drizzled over the blueberries, this bread tastes decadent but is really easy! Perfect for brunch!

Blueberry Lemonade with Vodka– this is one of those dangerous drinks because it tastes so delicious that you could easily drink too many! Feel free to leave the vodka out too and just have a non-alcoholic blueberry lemonade!

Blueberry Wine Slushies– these actually are blueberry and strawberry wine slushies and are layered for a red, white and blue effect! You could just make one flavor or all 3! Either way, they’re delicious!

Print Recipe
4.80 from 5 votes

Blueberry Crumble Bars

A buttery, oatmeal base and crumb topping with a homemade blueberry filling in the middle. A delicious dessert that feeds a crowd!
Prep Time15 minutes
Cook Time35 minutes
Resting time2 hours
Total Time50 minutes
Course: Dessert
Cuisine: American
Keyword: easy blueberry crumble bars
Servings: 24
Calories: 294kcal
Author: Natalie Dixon


Oatmeal Crumb Layer

  • 1.5 cups Butter
  • 3 cups Rolled Oats
  • 3 cups All-purpose Flour
  • 2 cups Light Brown Sugar
  • 1 tsp Baking Powder
  • 1/2 tsp Salt

Blueberry Filling

  • 2 cups Blueberries
  • 1/2 cup Sugar
  • 2 Tbsp. Cornstarch
  • 2 Tbsp. Lemon Juice


Oatmeal Crumb Layer

  • Preheat oven to 350 degrees.
  • In a large bowl, melt butter. Add remaining crumb ingredients to melted butter. Stir well until completely combined.
  • Press about 2/3 crumb mixture into the bottom of a 13x9 pan. Press down well. Bake for 10 minutes.

Blueberry Filling

  • In a medium saucepan, add all ingredients for the blueberry filling. Bring to a boil while stirring constantly. Continue stirring until the mixture has thickened, about 2-3 minutes.
  • Spread filling over baked crust. Sprinkle reserved crumbs over filling.
  • Bake for about 25 minutes until the crust just begins to turn a light, golden brown. Remove from oven and cool.


I usually place the cooled bars in the fridge for a couple hours to help them set faster.
Rolled oats work best for this recipe, but I've also used instant oats if that's all I have on-hand.
These can be stored at room temperature or in the fridge. I prefer to eat them chilled from the fridge!

easy blueberry crumble bars

You Might Also Like

No Comments

Leave a Reply

Recipe Rating

This site uses Akismet to reduce spam. Learn how your comment data is processed.