Blueberry Oatmeal Bars
If you’re looking for a simple, healthy blueberry dessert that actually turns out right every time, these blueberry oatmeal bars are it.
They’re soft, slightly crumbly, naturally sweetened and packed with juicy blueberry filling. This is the kind of recipe you can make once and then come back to all summer.
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Why You’ll Love These
- Made with simple pantry ingredients
- Naturally vegan and gluten free
- A perfect balance of soft base + jammy filling + crumble topping
- Works with fresh or frozen blueberries
What Makes This Recipe Better
This is an updated version of the recipe I first shared back in 2018 that fixes a few common issues:
- The base holds together better (no more crumbly bars falling apart)
- The filling sets properly (thanks to the cornstarch method)
- The texture is softer and more cohesive overall
When to Make These
These bars work for:
- Breakfast (they’re genuinely not too sweet)
- Afternoon snacks
- Meal prep
- A light summer dessert
Step-by-Step Instructions
Make the dough: The mixture might feel slightly dry at first; that’s normal. It should hold together when pressed, even if it doesn’t feel soft.
Press the base: Using your fingers works best here, as it helps you push the dough firmly into the corners and create an even layer. Take a moment to really compact it so the bars hold together later.
Cook the filling: Once the blueberries start bubbling, they’ll release a lot of juice and the filling might look a bit watery. But after adding the cornstarch mixture, it thickens quickly and turns glossy, almost like a loose jam.
Spread filling over the base: Move quickly to assembling before the filling starts to set and form a crust. Use a spatula or the back of a spoon to even out the surface.
Assemble: Because the dough has been chilled, it becomes much more crumbly. Break it into small pieces with your hands. Smaller crumbles stick better and give a more even topping.
Cool and slice: The bars will still feel soft when they come out of the oven, but they firm up as they cool. Letting them set fully is what gives you clean slices instead of a crumbly texture.
Tips for Best Results
- If your dough isn’t holding together, your oat flour may be coarser; add water gradually until it binds
- For extra clean slices, chill the bars before cutting
- Using frozen blueberries may slightly increase cooking time
- The crumble will soften slightly when stored in the fridge
Storing Instructions
Store in an airtight container:
- Room temperature: up to 3 days
- Fridge: up to 1 week
- Freezer: up to 3 months (defrost overnight)
FAQs
Yes — use them straight from frozen.
They likely weren’t cooled long enough. Let them fully set before slicing.
You can experiment with reducing or replacing the sugar, but it will slightly affect texture.
More Summer Berry Recipes
Blueberry Oatmeal Bars
Ingredients
Base & Crumble
- 1 ¼ cup (150 g) oat flour
- 1 cup (80 g) rolled oats
- ⅓ cup (65 g) cane sugar
- ⅓ cup (80 g) coconut oil, melted
- 1 teaspoon vanilla extract
Blueberry Filling
- 2 ½ tablespoons cornstarch
- Juice from 1 lemon
- 2 cups (250 g) blueberries, fresh or frozen
- ¼ cup (100 g) maple syrup
Instructions
- Preheat oven to 180°C (350°F). Line an 8×8-inch pan with parchment paper.
- In a large bowl, mix oat flour, rolled oats, sugar, coconut oil and vanilla. Use your hands to bring it together into a dough. If the mixture feels too dry to stick together, add 1–2 tablespoons of water until it holds when pressed. It doesn’t need to be soft, just able to hold its shape.
- Press ⅔ of the dough firmly into the pan, making sure it’s evenly packed and reaches all corners. The mixture may feel slightly dry, so press it down well to help it hold together. Place the pan and remaining dough in the fridge while you make the filling.
- To prepare the filling, whisk the cornstarch with lemon juice in a small bowl until completely smooth.
- In a saucepan, heat blueberries and maple syrup over medium heat until they release juice and begin to bubble. If using frozen blueberries, start on low heat to prevent burning.
- Mash the blueberries and cook for another 2 minutes, stirring constantly. Some chunks can remain.
- Remove from heat and whisk in the pre-mixed cornstarch. The filling should turn thick, glossy, and dark in colour. It thickens quickly, so whisk continuously and move to assembling before it starts to set.
- Pour the filling over the prepared base. Use a spatula to even out the surface.
- Crumble the remaining dough on top into small pieces. Press lightly so it adheres, as larger chunks may fall off after baking.
- Bake for 30–35 minutes, until the top is golden and the filling is visibly bubbling at the edges.
- Cool completely in the pan for at least 3 hours before slicing. Cutting too early will cause the bars to fall apart. For cleaner slices, you can chill them in the fridge.
- Once set, slice into 16 bars.
