Blueberry Oatmeal Bars
Blueberry Oatmeal Bars are the perfect summer breakfast made with an oatmeal crust topped with a lemon-blueberry filling, finished with a buttery crumb topping, ready in an hour!
Sweet and chewy blueberry oatmeal bars are the perfect summer breakfast or snack. They’re made with simple ingredients like rolled oats and fresh blueberries, and ready in just an hour. I love these bars because they’re simple to make, and you can even have them as a dessert paired with vanilla ice cream!
If you loved this recipe, you’ll also love my Gluten Free Blueberry Muffins, and my Gluten Free Blueberry Cobbler!
Table of contents
Why You’ll Love This Recipe
Soft and Chewy – These bars have a really nice soft and chewy texture from the oats, which pairs perfectly with a cup of coffee for breakfast!
Make-Ahead – These bars are even better after being stored in the refrigerator, so you can make them once and have grab-and-go breakfasts for the next few days!
Ingredients You’ll Need
Rolled Oats. For this recipe, it’s better to use Old Fashioned Oats (rolled oats) to get that chewy texture in the bars. I don’t recommend using quick oats or instant oats.
Make sure you choose certified gluten free oats, and if you need to you can check that they come from a company that uses a gluten free purity protocol (more on that here).
Gluten Free Flour. I like to use a cup-for-cup or 1:1 gluten free all-purpose flour that already has xanthan gum in the mixture, which helps hold everything together when you’re baking.
If you’re not gluten free, you can use the same amount of regular flour for this recipe.
Light Brown Sugar. This adds sweetness and moisture, and brown sugar has a deeper flavor. You could also use granulated sugar.
Spices. Adding some ground cinnamon and a dash of nutmeg adds a really nice flavor to the crumble. And a small amount of kosher salt helps balance out the sweetness.
Baking Powder. This will give the crumble a little bit of rise so it’s not too dense.
Unsalted Butter. This helps add some fat to the crust and topping which gives it a lot of flavor. I like to use unsalted butter, so I can add as much salt as I’d like myself.
Blueberries. I use fresh blueberries for this recipe. If you’re using frozen blueberries, I recommend defrosting and draining them ahead of time.
Cornstarch. This helps make the blueberry filling jammy instead of too thin, so it stays in the bars when you cut them into squares.
Lemon Juice and Lemon Zest. This adds a really nice flavor to the blueberry filling, and also helps the filling become jammy and more firm.
Granulated Sugar. The blueberries have a lot of natural sweetness, but a little bit of sugar helps bring it out further.
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Kitchen Tools
For these blueberry oat bars, you’ll need an 8×8″ baking pan, parchment paper, and a mixing bowl.
How to Make Blueberry Oatmeal Bars
Preheat oven to 375°F. Line an 8×8″ pan with parchment paper and set aside.
In a medium mixing bowl, whisk together the oats, gluten free flour, brown sugar, spices, and baking powder.
Add the pieces of butter and use your hands to combine the butter with the flour mixture until it resembles a wet crumb.
Set aside half of the crumble mixture, and firmly press the other half into the bottom of the pan in an even layer.
In a clean bowl, stir together the blueberries with the cornstarch, lemon juice, lemon zest, and sugar. Pour the blueberries on top of the crust, using a spoon to spread them out into an even layer.
Sprinkle the remaining crumble on top of the blueberries evenly.
Bake for 35-40 minutes, or until the blueberries are bubbly and the top is golden brown.
Remove from the oven and cool completely before cutting into squares.
Recipe Variations
- Try making this with other fruit like strawberries, raspberries, peaches, pitted cherries, or a mix of all of them!
- Try adding some chopped nuts to the top like almonds, pecans, or walnuts.
- If you’d like more toppings, try shredded coconut, chocolate chips, or a powdered sugar glaze.
Recipe Tip! You want the butter to be soft and a little cool to make the crumb topping just right. If the butter is too warm or melted, it will make the crumb too dense.
Frequently Asked Questions
There’s a few reasons this can happen, the most common being that you cut into them while they were still too warm. Give the bars a chance to completely cool off before cutting into them so the middle has a chance to set.
If you’re gluten free, make sure the flour blend you’re using contains xanthan gum, which helps hold everything together.
Recipe Tip! Press the base firmly into the bottom of the pan so it holds together and doesn’t break apart after baking. You can use the bottom of a measuring cup to help you do this.
More Oatmeal Recipes
Storage
Refrigerate blueberry oatmeal bars in an airtight container for 3-4 days.
Freeze leftover bars in a freezer-safe container for 2-3 months. If you wrap them individually, you can pull them out as you want them instead of defrosting everything at once.
Cooking Tips
- Be careful not to over-mix the oat mixture. After adding the butter, you want the dry ingredients to look wet and everything to be combined, but not over-worked. This will keep the base and topping tender and not dense.
- When the blueberry crumble bars are done, the middle should be bubbling and the top should be golden brown. As the bars cool, it will set and become more jammy than liquid.
- Let the bars cool completely to give the middle a chance to set. Once they’re not hot anymore, you can refrigerate them to make this go faster. The colder they are, the better they’ll hold together when slicing.
- You should be able to lift the bars out by the parchment paper to make it easier to cut them evenly. Make sure you leave some parchment paper on the sides when you’re pouring the filling in, so you have pieces to grab onto.
- To make it faster, you can also pulse the flour mixture and butter in the food processor until it comes together. You’ll still have to press it into the pan afterwards.
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Blueberry Oatmeal Bars
Equipment
- 1 8×8" baking dish with parchment paper
- 1 medium mixing bowl
Ingredients
- 1 1/2 cups old-fashioned rolled oats, certified gluten free
- 1 cup gluten free all-purpose flour, 1:1
- 1/2 cup light brown sugar
- 1 teaspoon baking powder, double-acting
- 1 teaspoon ground cinnamon
- 1/4 teaspoon ground nutmeg
- 1/2 teaspoon kosher salt
- 8 tablespoons unsalted butter, cold, broken into pieces
For the Blueberries
- 2 cups fresh blueberries
- 2 tablespoons lemon juice
- 1 tablespoon lemon zest
- 1 tablespoon cornstarch
- 3 tablespoons granulated sugar
Instructions
- Preheat oven to 375°F. Line an 8×8″ pan with parchment paper and set aside.
- In a medium mixing bowl, whisk together the oats, gluten free flour, brown sugar, spices, and baking powder. Add the pieces of butter and use your hands to combine the butter with the flour mixture until it resembles a wet crumb.
- Set aside half of the crumble mixture, and firmly press the other half into the bottom of the pan in an even layer.
- In a clean bowl, stir together the blueberries with the cornstarch, lemon juice, lemon zest, and sugar. Pour the blueberries on top of the crust, using a spoon to spread them out into an even later.
- Sprinkle the remaining crumble on top of the blueberries evenly. Bake for 35-40 minutes, or until the blueberries are bubbly and the top is golden brown. Remove from the oven and cool completely before cutting into squares.
Notes
- Press the base firmly into the bottom of the pan so it holds together and doesn’t break apart after baking. You can use the bottom of a measuring cup to help you do this.
- Be careful not to over-mix the oat mixture. After adding the butter, you want the dry ingredients to look wet and everything to be combined, but not over-worked.
- When the bars are done, the middle should be bubbling and the top should be golden brown.
- Let the bars cool completely to give the middle a chance to set.
- You should be able to lift the bars out by the parchment paper to make it easier to cut them evenly. Make sure you leave some parchment paper on the sides when you’re pouring the filling in, so you have pieces to grab onto.
Nutrition
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