Blueberry Oatmeal Bars

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Golden, crumbly, and loaded with juicy blueberries, these Blueberry Oatmeal Bars are the kind of treat that feels like a cozy hug in dessert form. They strike the perfect balance between tart fruit filling and a buttery oat crust, making them ideal for brunch, snacking, or an after-dinner indulgence.

What makes them special is the simplicity of the ingredients and the rustic texture from oats. You get a burst of fresh blueberry in every bite, surrounded by a chewy, buttery crust and streusel topping. Whether you use fresh or frozen blueberries, the result is always beautifully jammy and satisfying.

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What Kind of Oats Should I Use?

Old-fashioned rolled oats are the best choice here. They provide a hearty, chewy texture that holds up during baking and contrasts nicely with the soft blueberry layer. Instant oats tend to get mushy, while steel-cut oats are too tough and don’t soften enough in the oven.

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Ingredients for the Blueberry Oatmeal Bars

Blueberries
This is the heart of the filling. Blueberries bring that sweet-tart balance and juicy texture that makes these bars so addictive.

Old-Fashioned Rolled Oats
Oats provide a chewy bite and rustic flavor. They also form the base of the crust and crumb topping.

All-Purpose Flour
Essential for structure. It binds the oats and butter together, giving the bars stability.

Butter
Unsalted butter gives the bars their richness and allows for a perfectly crisped crust and crumbly topping.

Brown Sugar
Used for its moisture and deep caramel flavor. It enhances the warmth of the oatmeal base.

Granulated Sugar
Sweetens the blueberry filling just enough to make it jammy but not overly sugary.

Cornstarch
Thickens the blueberry mixture, helping it set up cleanly once cooled.

Lemon Juice and Zest
Adds brightness and lifts the blueberry flavor so it doesn’t feel too heavy.

Salt
Just a pinch to enhance all the other flavors.

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How To Make the Blueberry Oatmeal Bars

Step 1: Preheat and Prepare the Pan

Start by preheating your oven to 350°F (175°C). Line an 8×8-inch square baking pan with parchment paper, leaving overhang for easy removal.

Step 2: Mix the Crust and Topping

In a large bowl, combine the old-fashioned oats, flour, brown sugar, and salt. Stir in the melted butter until the mixture turns crumbly and moist. Reserve about 1 cup of this mixture for the topping. Press the rest into the bottom of your prepared pan to form an even crust.

Step 3: Make the Blueberry Filling

In another bowl, toss together the blueberries, granulated sugar, cornstarch, lemon juice, and zest until the berries are well coated and glossy. Spoon this mixture evenly over the crust.

Step 4: Add the Crumb Topping

Sprinkle the reserved oat mixture evenly over the blueberry layer. Pat it down very lightly to help it stick.

Step 5: Bake to Golden Perfection

Bake in the preheated oven for 35-40 minutes, or until the topping is golden and the blueberries are bubbling.

Step 6: Cool and Slice

Let the bars cool completely in the pan. For the cleanest slices, chill them in the fridge for at least an hour before lifting out and cutting into squares.

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Serving and Storing Blueberry Oatmeal Bars

These bars are delicious served slightly warm or completely chilled. Pair with a scoop of vanilla ice cream for dessert or a cup of coffee for a mid-morning treat.

To store, keep them in an airtight container at room temperature for up to 2 days, or refrigerate for up to a week. For longer storage, freeze the bars in a single layer, then transfer to a zip-top bag for up to 3 months. Thaw at room temperature or gently warm in the microwave.

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Frequently Asked Questions

How do I prevent soggy bottoms on the bars?

Make sure to fully pre-bake the bottom crust before adding the filling if your blueberries are especially juicy. Also, chilling the bars after baking helps them set properly.

Can I use frozen blueberries?

Yes! No need to thaw them. Just toss with the other filling ingredients and bake a few minutes longer if needed.

Are these bars gluten-free?

You can make them gluten-free by using certified gluten-free oats and a gluten-free all-purpose flour blend.

Can I double this recipe?

Absolutely. Just use a 9×13-inch pan and add a few minutes to the baking time.

What’s the best way to cut clean slices?

Chill the bars in the fridge for at least an hour. Then use a sharp knife, wiping it clean between cuts.

Can I use other fruits?

Definitely! Try raspberries, blackberries, or chopped peaches. Adjust the sugar and cornstarch as needed based on their sweetness and juiciness.

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Want More Dessert Ideas?

You might also like the Raspberry Crescent Rolls, which deliver a fruity filling wrapped in flaky dough. Or for something indulgent and creamy, the No-Bake Banana Pudding Cheesecake is a crowd favorite.

For a bite-sized delight, check out the Cheesecake Deviled Strawberries. If you’re looking for something rich and chocolatey, don’t miss the Indulgent Chocolate Chess Pie.

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Pin and Tell Me How Yours Turned Out

You can save this to your dessert boards for next time. Just click the Pin button.

If you make it, I’d love to hear how it turned out. Did you use fresh or frozen berries? Did you add a twist of your own? Leave a comment below. I’m always curious how others bake it.

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