EASY blueberry blondies with a quick crumble topping! They are a classic soft and chewy blondie bar; made with simple ingredients and bursting with blueberries.

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Blondie bars are super simple to make and are a great bar cookie when you are a busy baker. Blueberry blondies add a burst of fruit and the easy crumble topping {reminds me of my raspberry crumble cookies} takes these cookie bars from boring to irresistible!

If you are in the mood for more blueberry recipes try my blueberry pie or lemon blueberry cookies or blueberry ricotta cake. For breakfast ideas try my healthy lemon blueberry muffins or easy blueberry coffee cake. And if you're in the mood for ice cream try my white chocolate ice cream with roasted blueberries!

Why you will love this blondie recipe

Quick and easy ~ simple ingredients come together in two bowls to make these scrumptious blondie bars.
Soft and chewy ~ blueberry crumble blondies have a dense and chewy, soft and tender texture.
Crumble topping ~ a super easy crumble is added over the batter to give this blondie recipe a little something special.
Melted butter means no planning ahead!
No mixer required.

what are blondie bars?

Blondies are similar to brownies, but are made with brown sugar and no cocoa powder or melted chocolate. They are a classic American cookie bar that have a texture like brownies, but a more caramel-like flavor as they have a vanilla base made with brown sugar.

Blondies can be plain, but are often loaded with nuts, chocolate chips or chopped candies. Today we are adding flavorful blueberries.

ingredients needed

Please scroll to the printable recipe card at the end of this post for the full list of ingredients and baking directions.

Butter ~ you need melted, unsalted butter for both the crumble and blondies.
Brown sugar ~ the signature mark of a blondie recipe. I prefer dark brown sugar, but light brown sugar or a combination can also be used.
Granulated sugar ~ used in both the crumble and the blueberry blondies.
Egg ~ you will need one large egg.
Vanilla ~ adds flavor; I prefer a pure vanilla extract.
Cornstarch ~ helps to add softness to the blondie bars. If you don't have cornstarch, use two tablespoons of all-purpose flour in it's place.
Baking powder ~ to give the blondies a little lift.
Kosher salt ~ helps to balance all the flavors. If you only have table salt use half the amount.
All-purpose flour ~ gives structure to the blueberry blondies. For gluten free blondies, use a one-to-one flour replacement.
Blueberries ~ my preference is fresh blueberries, but frozen blueberries can also be substituted. See the recipe card for how to use them.

how to make blueberry crumble blondies

Start by preheating the oven to 350°F and line an 8x8 baking pan with parchment paper and lightly butter or spray with non-stick spray.

Next make the crumble; in a medium bowl mix together the all-purpose flour and granulated sugar. Then pour the melted butter over the dry ingredients and stir with a fork until a clumpy mixture forms. Set aside.

Now in a large bowl, mix together the melted butter, brown sugar and granulated sugar until well combined.

Then add the egg and vanilla. Scrape the bowl as needed and beat until combined. Now add the cornstarch, baking powder and kosher salt and mix until well combined.

crumble topping in a bowl with a fork — Use a fork to mix the melted butter into the flour and sugar until it gets clumpy.

melted butter and sugars mixed in a bowl — The butter won't fully mix with the sugar until the egg is added.

blondie batter after the egg and vanilla have been mixed in — The batter becomes more cohesive after the eggs and vanilla have been fully mixed in.

Next add the all-purpose flour and mix until some large flour streaks remain. Then add about ¾ of the blueberries and gently fold to combine.

blondie batter with some large patches of flour remaining — Mix in the flour until some large patches of flour remain.

blueberries folded into the blondie batter — Use a spatula to gently fold the blueberries into the batter.

Drop the batter {it’s thick} into the prepared baking pan and smooth to an even layer.

Then sprinkle the crumble and remaining blueberries over the top.

Bake until the edges have browned and a tester in the center comes out with just a few moist crumbs.

blueberry blondie batter in a parchment lined baking pan. — Spread the batter in an even layer in a parchment lined baking pan.

crumble and blueberries sprinkled over the blondie batter — Sprinkle the crumble over the blondie batter and top with the remaining blueberries.

baked blueberry blondies in the baking pan — The blueberry blondies are done when the edges are golden and a toothpick comes out with just a few moist crumbs.

tips for making the best blondie bars

Using a kitchen scale will be more accurate than measuring cups, especially for the flour and blueberries.
Gently fold in the blueberries to avoid smooshing them into the batter.
Brown sugar is a key ingredient in tasty blondie recipes. You can use dark brown, light brown or a combination. If all dark brown sugar is used you'll have a touch more moisture and sweetness.
The cornstarch adds to the chewy and soft texture. It's an excellent secret ingredient that I also use in my blackberry coffee cake.
If using frozen blueberries in this quick and easy recipe, don't defrost them first.
For neatly cut bars; the blondie bars should be completely cool {chilling them will also help}. Use a sharp knife and wipe it clean between each cut.

variation ideas

My taste testers found these blueberry blondies to be perfectly sweet, but here are some ideas for making them your own.

Lemon blueberry blondies ~ add lemon zest to the batter. I would use 1-2 tablespoons of zest. A lemon glaze would also be lovely; this scone recipe uses my favorite lemon glaze.

White chocolate blueberry blondies ~ add ½ cup of white chocolate with the blueberries. You could also drizzle a little melted white chocolate over the top. I would use 1-2 ounces of white chocolate.

If you are in the camp of liking a more cake-like bar; add one extra egg. I'd call this version more of a blueberry crumble cake {it wasn't the texture I was going for} and it's downright delish!!

frequently asked questions

is a blondie the opposite of a brownie?

Blondie bars are often called blonde brownies. Both are dessert bars, but blondies have a vanilla and brown sugar base while brownies use chocolate and cocoa.

why are my blondies raw in the middle?

The oven might not be at the correct temperature. I keep an oven thermometer in my oven so I can make sure it's at the temperature I think it is. A too hot oven will cause the edges to over bake before the middle has a chance to fully cook.

If you use a glass pan, it could take up to double the amount of baking time as glass conducts heat differently then metal.

The blueberry blondies could also be under baked. When you test them with a toothpick, a few moist crumbs is ideal. If the toothpick has wet batter, bake your blondies a little longer.

can I use frozen blueberries?

Yes, you can use frozen blueberries. Do not thaw the blueberries before adding them to the batter. The frozen blueberries may color blondie bars a bit bluish purple.

can I use a different berry?

Yes! You can use raspberries, blackberries or strawberries in this blondie bar recipe.

how to store

Blueberry blondies will stay fresh in an airtight container at room temperature for 1-2 days or can be stored in an airtight container in the refrigerator for up to 5 days.

They also freeze well for up to three months; allow to defrost before serving. Serve chilled or at room temperature.

blueberry blondies on a parchment lined cooling rack

Remember to snap a picture and tag me on Instagram if you make these EASY Blueberry Blondies. It warms my heart to see you bring these recipes to life! Thank you for being here and happy baking!

other blondie bars to try

If you make this recipe {or any recipe!} from two sugar bugs please come back and leave a review and a ⭐️⭐️⭐️⭐️⭐️ star rating. I read every comment, and I LOVE hearing from you!

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