These easy Berry Oatmeal Crumble Bars are the perfect use for fresh summer berries!  A crispy oatmeal shell surrounding a sweet homemade berry jam – delicious with blueberries, blackberries, raspberries, or strawberries!

Summer’s here – and with it, all the delicious fresh summer produce!  My favorite is all the BERRIES – I love blueberries, blackberries, and raspberries.  (Strawberries, you’re okay too.)

Do you ever have the “eyes bigger than your stomach” problem and buy All! The! Berries!. and then realize you can’t finish them up before they start to get a little mushy and soft?  Worry no more – I’m here to help you with your berry overload.

I could probably eat fresh blueberries by the pound, so using up berries isn’t a problem I usually have.  But if I did, these berry oatmeal crumble bars would be my favorite way to use every last one!

I’ve tried these with all sorts of berries  — blackberries, blueberries, raspberries, strawberries, and combinations involving all of the above.  Every flavor combination has turned out delicious!  The only possible way to make these any better?  Serve with a big scoop of ice cream on top!

The crunchy oatmeal topping, the sweet jam-like filling – these berry oatmeal crumble bars are the perfect summery treat!  Stop by your farmer’s market and pick up a pint or two of fresh berries to make these – long live summer.

Easy Oatmeal Crumble Crust

The foundation of our Berry Oatmeal Crumble Bars is the oatmeal crumble crust. It provides a delightful texture and adds a slightly nutty flavor to the bars. The ingredient list for the crust is quite simple: flour, oats, brown sugar, butter, baking soda, salt, and vanilla extract.

To keep these bars gluten-free, swap your favorite 1:1 gluten-free baking mix for the all-purpose flour (or since the crust doesn’t require too much rise, you can even use almond flour instead!)

For a vegan version, swap out the butter for plant-based margarine or frozen coconut oil. (We want to be able to cut the fat into the oat and flour mixture, which is why we want the coconut oil to start out frozen, rather than liquid at room temperature.)

One important tip: make sure to use old-fashioned rolled oats and not instant oatmeal! We need the texture and chew from the larger rolled oats, not the paper-thin instant oats.

You can make the crust either by hand, using two forks or a pastry cutter to cut in the cold butter, or in a food processor to make it even easier!

Homemade Jam Filling

Yes, you could use store-bought jam for these (actually, just make this Oatmeal Jam Bar recipe if you want to do that!), but we’re going to take advantage of beautiful fresh berries and make our own jam!

This is a super easy stovetop jam, made without adding additional pectin or other stabilizers. How does this work? It’s time for my favorite subject… kitchen chemistry!

Kitchen Chemistry

Pectin is a naturally occuring soluble fiber found in fruits. When heated an acid, pectin forms a gel-like structure, resulting in the characteristic consistency of jam. Berries, such as strabwerries and raspberries, contain enough natural pectin for the jam to set without requiring added pectin, as is the case for many other fruits.

Even with natural pectin, however, jam can sometimes still be a little too… gooey. We don’t want the jam oozing out of the sides of our berry oatmeal crumble bars! So we’ll prevent this by adding a little cornstarch to the mixture as it thickens. This cornstarch will bind to any excess water molecules.

Recommended Tools to Make Berry Crumble Bars

• 2 Quart Saucepan: Use a small heavy-bottomed saucepan like this to make the homemade berry jam.
• Mixing Bowls: This recipe calls for multiple mixing bowls and this set includes all the sizes you need (plus glass is dishwasher and microwave-safe!).
• 9×13-inch Baking Pan: Light-colored metal baking pans, like the one linked, provide the most consistent heat transfer without excessively browning the edges of your baked goods.
• Food Processor: While you can cut the butter into the flour by hand, a food processor makes the process super quick!

Tips and Tricks for the Best Berry Oatmeal Crumble Bars

1. If you love lemon, add a teaspoon of lemon zest to the oatmeal crumble mixture for an even more delicious flavor.
2. Add your favorite baking spices to the jam for a deeper, more complex flavor. Some of my favorites include adding a teaspoon or two of cinnamon, vanilla extract, or cardamom.
3. Make sure your butter is cold when making the oatmeal crumble. Cold butter helps create a flaky texture and prevents the mixture from becoming greasy.
4. Don’t overmix the crust – we want some large clumps to remain for the crumbly topping.
5. Berry oatmeal crumble bars can be stored at room temperature in an air-tight container for up to 3 days, refrigerated for up to a week, or frozen for up to 3 months. Store with parchment paper between layers of the bars to prevent them from sticking to each other.

More Fresh Berry Recipes

• Vanilla Blueberry Cake with Blueberry Cardamom Curd
• Chocolate Strawberry Pie
• Berry Pavlova with Lemon Curd Cream
• Raspberry Crumb Cake
• Summer Berry Trifle