Okay, friends—gather ‘round, because today we’re whipping up something that tastes like a warm hug from summer, no matter the season. These Mixed Berry Oatmeal Crumble Bars are gooey, buttery, and loaded with jammy berry goodness tucked between layers of golden, toasty oat crumble. You’re going to want to bookmark this one!
Why You’ll Love This Recipe
These bars came to life one crazy afternoon when my kiddos wanted dessert, and my fridge only had a handful of leftover berries and a half-eaten stick of butter. Fast forward—and this has become a weekly treat everyone requests. It’s easy enough for a bake sale and delightful enough to serve with a cup of coffee when company pops by.
- One bowl, no mixer required—yes, seriously.
- Perfect balance of tart berries and sweet, buttery crumble.
- Freezer-friendly, so you can always have a snack on hand.
- Made with pantry staples—oats, flour, sugar, and butter.
- Easily adaptable for various berries or even jams.
Ingredients Breakdown
Essentials
- 1 1/2 cups old-fashioned rolled oats
- 1 1/4 cups all-purpose flour
- 1/2 cup brown sugar, packed
- 1/4 cup granulated sugar
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 3/4 cup unsalted butter, melted
- 1 teaspoon vanilla extract
- 2 cups mixed berries (fresh or frozen—blueberries, raspberries, blackberries, strawberries)
- 1 tablespoon cornstarch
- 2 tablespoons lemon juice
- 3 tablespoons sugar (for the fruit layer)
Pro Tips
- If using frozen berries, no need to thaw—just toss with cornstarch and lemon juice straight from the freezer.
- Add a pinch of cinnamon to the oat mixture for a cozy flavor twist.
- Use coconut sugar instead of brown sugar for a refined sugar-free version.
- Lining your pan with parchment paper makes for easy removal and cleaner slices.
Step-by-Step Instructions
- Preheat your oven to 350°F (175°C). Grease or line an 8×8-inch baking dish with parchment paper.
- In a large bowl, mix together oats, flour, brown sugar, granulated sugar, baking soda, and salt.
- Stir in the melted butter and vanilla until the mixture is crumbly and evenly moistened.
- Press about two-thirds of the oat mixture firmly into the bottom of the prepared pan.
- In a separate bowl, gently toss the berries with cornstarch, lemon juice, and sugar.
- Spread the berry mixture evenly over the crust.
- Sprinkle the remaining oat crumble on top of the berry layer.
- Bake for 35–40 minutes or until golden brown and bubbly.
- Let cool completely in the pan before slicing into bars. (Trust me, it’s worth the wait!)
Chef’s Tips and Tricks
- Press the crust down firmly with the bottom of a measuring cup to get a solid base.
- Allow the bars to cool completely before cutting—this helps them hold together neatly.
- Store leftovers in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days.
- For neat squares, chill the bars for 30 minutes before slicing.
Recipe Variations and Serving Suggestions
- Swap in chopped apples and a touch of cinnamon for a fall-friendly version.
- Use raspberry or strawberry jam in place of fresh berries for a shortcut.
- Top warm bars with a scoop of vanilla ice cream for dessert heaven.
- Drizzle with maple glaze or a dusting of powdered sugar for extra flair.
- Turn it into a breakfast bar by adding chopped walnuts or almonds to the topping for some protein power.
FAQs
Can I use frozen berries?
Absolutely! Just add them straight from the freezer—no need to thaw. The cornstarch and lemon juice will help thicken any extra juices during baking.
How can I make this gluten-free?
Swap the all-purpose flour for a gluten-free 1:1 flour blend and be sure to use certified gluten-free oats. The texture stays pretty spot-on!
Can I double the recipe?
You bet! Just bake it in a 9×13-inch pan and add a few more minutes to the bake time—watch for that beautiful golden top.
Recipe Card
Prep Time: 15 minutes
Cook Time: 40 minutes
Total Time: 55 minutes
Ingredients:
- 1 1/2 cups old-fashioned rolled oats
- 1 1/4 cups all-purpose flour
- 1/2 cup brown sugar, packed
- 1/4 cup granulated sugar
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 3/4 cup unsalted butter, melted
- 1 teaspoon vanilla extract
- 2 cups mixed berries (fresh or frozen)
- 1 tablespoon cornstarch
- 2 tablespoons lemon juice
- 3 tablespoons sugar (for the fruit layer)
Instructions:
- Preheat oven to 350°F and prepare an 8×8-inch pan.
- Mix oats, flour, sugars, baking soda, and salt in a large bowl.
- Stir in melted butter and vanilla until crumbly.
- Press 2/3 of the mixture into the pan for the crust.
- Toss berries with cornstarch, lemon juice, and sugar. Spread over crust.
- Sprinkle remaining oat mixture on top.
- Bake 35–40 minutes until golden and bubbly. Cool completely before slicing.
Nutrition: ~220 calories per serving
If you make these Mixed Berry Oatmeal Crumble Bars, don’t forget to leave a comment below and let me know how they turned out! Tag me on Instagram @thekitchensaid—seeing your kitchen magic totally makes my day!
