Why You’ll Love This Strawberry Oat Crumble Bars
- They’re the perfect texture party. You get a firm, slightly crumbly base, a soft and juicy fruit center, and a crispy, nutty topping all in one bite. It’s a symphony of contrasts that is just so satisfying to eat.
- They’re incredibly versatile. While we’re using strawberries here, this recipe is a fantastic blueprint. You can easily swap in blueberries, raspberries, peaches, or even a mix of your favorite summer fruits. It’s a great way to use up whatever looks good at the market.
- They’re deceptively easy. There’s no rolling pin required, no fussy lattice work. The same mixture forms the base and the crumble topping, which means less cleanup and less stress. It’s a one-bowl wonder (almost!).
- They feel wholesome without sacrificing flavor. The oats add a lovely heartiness and fiber, making these bars feel a bit more substantial than a standard pastry. But don’t worry—they’re still delightfully sweet and indulgent.
Ingredients & Tools
- 300 g all-purpose flour
- 200 g old-fashioned rolled oats (not instant)
- 220 g light brown sugar, packed
- 1/2 tsp baking powder
- 1/2 tsp fine sea salt
- 280 g unsalted butter, cold and cubed
- 500 g fresh strawberries, hulled and chopped
- 100 g granulated sugar
- 2 tbsp cornstarch
- 1 tbsp fresh lemon juice
- 1 tsp vanilla extract
Tools: 9×13 inch baking pan, parchment paper, a large mixing bowl, a pastry cutter or your fingertips, a medium saucepan.
The quality of your butter really shines here, so if you can, use a good one. And for the strawberries, fresh is best for that bright, authentic flavor, but frozen will work in a pinch—just don’t thaw them completely before using.
Serves: 12-16 bars | Prep Time: 20 minutes | Cook Time: 45-50 minutes | Total Time: about 1 hour 15 minutes (plus cooling)
Before You Start: Tips & Ingredient Notes
- Keep that butter cold! This is the secret to a flaky, crumbly texture. If the butter melts before it hits the oven, the crust and topping can become greasy and dense. Work quickly and pop the bowl back in the fridge for 10 minutes if your kitchen is warm.
- Why old-fashioned oats? They provide a much better texture than quick-cooking oats. They hold their shape and give you that wonderful chewy, nutty bite. Quick oats can turn a bit mushy.
- Don’t skip the cornstarch. Strawberries release a lot of juice as they bake. The cornstarch acts as a thickener, ensuring your filling is gloriously jammy and not a soupy mess. It’s the key to a bar that holds its shape when you cut it.
- A pinch of salt is your friend. It might seem like a small thing, but salt balances the sweetness and enhances all the other flavors, making the strawberries taste even more strawberry-like.
How to Make Strawberry Oat Crumble Bars
Step 1: Prepare Your Pan and Preheat. First things first, preheat your oven to 350°F (175°C). This gives it plenty of time to come to the right temperature. Line your 9×13 inch baking pan with parchment paper, leaving some overhang on the two long sides. This little trick is a lifesaver—it creates a sling that makes lifting the entire batch of bars out of the pan for clean cutting an absolute breeze. Lightly grease the exposed short sides of the pan.
Step 2: Make the Oat Crumble Mixture. In your large mixing bowl, whisk together the flour, oats, brown sugar, baking powder, and salt. Add the cold, cubed butter. Now, using a pastry cutter, two forks, or—my personal favorite—your clean fingertips, work the butter into the dry ingredients. You’re aiming for a crumbly texture with pea-sized bits of butter throughout. The mixture should hold together when you pinch a bit of it. This is your base AND your topping, so no need to dirty another bowl!
Step 3: Par-bake the Crust. Set aside about 1 and 1/2 cups of the crumble mixture for the topping. Press the remaining mixture firmly and evenly into the bottom of your prepared pan. You want to really compact it—this prevents it from getting soggy from the fruit filling. Use the bottom of a measuring cup to help you get a nice, even layer. Pop this into the preheated oven for about 15 minutes, just until it looks dry and is very lightly golden at the edges. This step gives the base a head start and ensures it bakes through completely.
Step 4: Create the Strawberry Filling. While the crust is baking, make the filling. In your medium saucepan, combine the chopped strawberries, granulated sugar, cornstarch, and lemon juice. Cook over medium heat, stirring frequently, for about 5-7 minutes. You’ll notice the strawberries will start to break down and release their juices, and the mixture will thicken and become glossy. Remove it from the heat and stir in the vanilla extract. Let it cool for just a few minutes—it will continue to thicken as it sits.
Step 5: Assemble the Bars. Once the crust is out of the oven, spread the warm strawberry filling evenly over the hot crust, going all the way to the edges. Now, take the reserved crumble topping and sprinkle it evenly over the strawberry layer. Don’t press it down—you want those lovely, loose crumbs to create a textured, crispy top.
Step 6: Bake to Golden Perfection. Place the pan back in the oven and bake for 30-35 minutes, or until the topping is a beautiful golden brown and the fruit filling is bubbling actively around the edges. That bubbling is your sign that the cornstarch has done its job and the filling is properly set.
Step 7: The Most Important Step—Cool Completely! I know, I know, this is the hardest part. But you must let the bars cool completely in the pan on a wire rack. I’d even recommend popping them into the refrigerator for an hour or two after they’ve reached room temperature. This allows the filling to fully set, which is what gives you those clean, perfect squares. If you cut into them while they’re warm, they’ll be deliciously messy, but they won’t hold their shape.
Serving Suggestions
Complementary Dishes
- A simple green salad with a lemon vinaigrette — The bright, acidic notes of the salad provide a lovely, refreshing contrast to the sweet, rich bars, making them feel like a more complete, balanced treat.
- A scoop of vanilla bean ice cream — This is the classic, and for good reason. The warm bar and cold, creamy ice cream create a divine temperature and texture contrast that is simply unbeatable.
Drinks
- A glass of cold whole milk — Sometimes the simplest pairings are the best. The creaminess of the milk is a timeless partner for any oat-based dessert and cools the palate beautifully.
- A cup of Earl Grey tea — The bergamot in the tea has a lovely citrusy flair that complements the strawberry filling wonderfully, making for a very sophisticated afternoon snack.
Something Sweet
- A small, dark chocolate espresso bean — Enjoy one of these after your bar for a hit of bitter, intense chocolate and coffee that cleanses the palate and ends the experience on a sophisticated note.
- A dollop of lightly sweetened whipped cream — If ice cream feels too heavy, a cloud-like puff of whipped cream adds a touch of luxury without overwhelming the delicate flavors of the bar itself.
Top Mistakes to Avoid
- Mistake: Using melted or softened butter. This is the number one reason for a dense, greasy bar. The cold butter creates little steam pockets as it bakes, which is what gives you that desirable flaky, crumbly texture. I’ve messed this up before too, and the difference is night and day.
- Mistake: Skipping the par-bake of the crust. That 15-minute head start is crucial. Without it, the bottom layer can end up undercooked and soggy from the wet fruit filling. It’s a small step that guarantees a perfect base.
- Mistake: Cutting the bars while they’re warm. I’m repeating this because it’s so important! Your patience will be rewarded with beautiful, neat squares. Cutting them warm leads to a gooey, albeit delicious, disaster.
- Mistake: Not pressing the base firmly enough. A loosely packed base will crumble when you try to cut the bars. Really use some muscle to press it into an even, compact layer.
Expert Tips
- Tip: Add a nutty crunch. For an extra layer of flavor and texture, stir 1/2 cup of chopped pecans or almonds into the crumble topping mixture before sprinkling it over the filling. It adds a wonderful toastiness.
- Tip: Grate your cold butter. If you want to speed up the process of cutting the butter into the flour, use the large holes of a box grater to grate your cold butter directly into the dry ingredients. It incorporates much faster and more evenly.
- Tip: Make them ahead! These bars are fantastic for making a day in advance. Once fully cooled and cut, store them in an airtight container at room temperature. They actually taste even better the next day as the flavors have more time to meld.
- Tip: Freeze for later. These bars freeze beautifully. Layer them in an airtight container with parchment paper between layers and freeze for up to 3 months. Thaw at room temperature whenever a craving strikes.
FAQs
Can I use frozen strawberries instead of fresh?
Absolutely! You don’t even need to thaw them completely. Just chop them while they’re still a bit frozen (it’s easier and less messy!) and use them directly in the filling. You might need to add an extra minute or two to the cooking time on the stovetop as they’ll release more water initially. The cornstarch will still thicken everything up perfectly.
My filling is too runny. What happened?
This usually means the filling didn’t cook long enough on the stovetop to activate the cornstarch, or the bars were cut before they were completely cool. Cornstarch needs to come to a simmer to reach its full thickening power. Next time, make sure the filling is visibly thickened and glossy before taking it off the heat. And remember, patience is key with cooling!
Can I make these gluten-free?
Yes, you can! Simply use a 1:1 gluten-free all-purpose flour blend in place of the regular flour. Make sure your oats are certified gluten-free, as oats are often processed in facilities that also handle wheat. The recipe will work just as well.
How should I store these bars?
Once cooled and cut, store them in an airtight container at room temperature for up to 3 days. If your kitchen is particularly warm or humid, you might want to store them in the fridge to keep the topping crisp. They can also be refrigerated for up to a week.
Can I reduce the amount of sugar?
You can, but with a few caveats. The sugar isn’t just for sweetness; it also helps with the texture of the crust and the setting of the fruit filling. If you reduce it, the crust might be more dry and shortbread-like, and the fruit filling might be tarter and slightly less jammy. I’d suggest trying a modest reduction of 1/4 cup in the crust and 2 tablespoons in the filling first to see how you like it.
Strawberry Oat Crumble Bars
Whip up these easy Strawberry Oat Crumble Bars! A buttery oat crust, jammy strawberry filling & crunchy topping. Perfect for picnics & potlucks. Simple, delicious recipe!
Ingredients
Ingredients
-
300 g all-purpose flour
-
200 g old-fashioned rolled oats (not instant)
-
220 g light brown sugar (packed)
-
1/2 tsp baking powder
-
1/2 tsp fine sea salt
-
280 g unsalted butter (cold and cubed)
-
500 g fresh strawberries (hulled and chopped)
-
100 g granulated sugar
-
2 tbsp cornstarch
-
1 tbsp fresh lemon juice
-
1 tsp vanilla extract
Instructions
-
Prepare Your Pan and Preheat. First things first, preheat your oven to 350°F (175°C). This gives it plenty of time to come to the right temperature. Line your 9x13 inch baking pan with parchment paper, leaving some overhang on the two long sides. This little trick is a lifesaver—it creates a sling that makes lifting the entire batch of bars out of the pan for clean cutting an absolute breeze. Lightly grease the exposed short sides of the pan.01
-
Make the Oat Crumble Mixture. In your large mixing bowl, whisk together the flour, oats, brown sugar, baking powder, and salt. Add the cold, cubed butter. Now, using a pastry cutter, two forks, or—my personal favorite—your clean fingertips, work the butter into the dry ingredients. You're aiming for a crumbly texture with pea-sized bits of butter throughout. The mixture should hold together when you pinch a bit of it. This is your base AND your topping, so no need to dirty another bowl!02
-
Par-bake the Crust. Set aside about 1 and 1/2 cups of the crumble mixture for the topping. Press the remaining mixture firmly and evenly into the bottom of your prepared pan. You want to really compact it—this prevents it from getting soggy from the fruit filling. Use the bottom of a measuring cup to help you get a nice, even layer. Pop this into the preheated oven for about 15 minutes, just until it looks dry and is very lightly golden at the edges. This step gives the base a head start and ensures it bakes through completely.03
-
Create the Strawberry Filling. While the crust is baking, make the filling. In your medium saucepan, combine the chopped strawberries, granulated sugar, cornstarch, and lemon juice. Cook over medium heat, stirring frequently, for about 5-7 minutes. You'll notice the strawberries will start to break down and release their juices, and the mixture will thicken and become glossy. Remove it from the heat and stir in the vanilla extract. Let it cool for just a few minutes—it will continue to thicken as it sits.04
-
Assemble the Bars. Once the crust is out of the oven, spread the warm strawberry filling evenly over the hot crust, going all the way to the edges. Now, take the reserved crumble topping and sprinkle it evenly over the strawberry layer. Don't press it down—you want those lovely, loose crumbs to create a textured, crispy top.05
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Bake to Golden Perfection. Place the pan back in the oven and bake for 30-35 minutes, or until the topping is a beautiful golden brown and the fruit filling is bubbling actively around the edges. That bubbling is your sign that the cornstarch has done its job and the filling is properly set.06
-
The Most Important Step—Cool Completely! I know, I know, this is the hardest part. But you must let the bars cool completely in the pan on a wire rack. I'd even recommend popping them into the refrigerator for an hour or two after they've reached room temperature. This allows the filling to fully set, which is what gives you those clean, perfect squares. If you cut into them while they're warm, they'll be deliciously messy, but they won't hold their shape.07
