Sweet, buttery, and the best blend of flavors, these Berry Crumb Bars will quickly be your new favorite summer dessert. A healthy fruit mix of either fresh or frozen berries is sandwiched between shortbread layers and baked to gooey perfection. Serve up this easy recipe all summer long when the grocery store is full of fresh berries, or toss in some frozen ones whenever the mood strikes.

Healthy, fruity, and delicious crumble bars are the best summer dessert.

Blueberry & Raspberry Crumb Bars Recipe

This berry crumb bar is the summer dessert recipe you didn’t even know you were missing.

Recently I had a couple of containers of fresh berries in my refrigerator that were about to go bad. Knowing I had a huge crew of runners with voracious appetites post-workout, I decided to whip up a quick treat.

I’d recently seen a post about raspberry crumb bars and another for blueberry crumble bars and was inspired. Why not combine them both along with some strawberries and blackberries for the best of all worlds?!

And the best it sure was!! This recipe is incredible.

The cookie-slash-shortbread crust doubles as the buttery crumb topping while the fresh berries bake in the oven to create this gooey-syrup-like filling that is the perfect balance of sweet and tart.

When blueberry season along with all the other berries hit in the summer, you NEED a great recipe like this in your back pocket.

Plus, the colors are perfect for those patriotic celebrations. These HAVE to make an appearance at your next July 4th or Labor Day barbecue! Or simply when you’re craving an afternoon snack.

Be sure to try this Mixed Berry Smoothie, as well!

Berries, flour, oats, butter, and sugar and the main ingredients for this dish.
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The simple ingredients you need to make this berry shortbread recipe you need:

  • Butter. Salted butter was used and is the best to ensure an even flavor throughout. If you go for unsalted butter, be sure to add extra salt to the shortbread mix.
  • Sugar. For the most authentic shortbread, stick with brown sugar. However, you can sub another sweetener, like stevia, if you’re avoiding processed sugars. You’ll need white, granulated sugar for the fruit layer.
  • Egg. You need one large egg at room temperature.
  • Flour. Depending on your dietary needs, go with all-purpose flour or a gluten-free 1-to-1 blend. Avoid almond flour as the grainy texture will affect the outcome.
  • Oats. Whole, rolled oats are best. If needed, ensure they’re gluten-free. Avoid steel-cut oats or quick oats as they will affect the texture of the shortbread.
  • Berries. A blend of fresh blueberries, strawberries, and blackberries makes the fruit base. You can stick with one type, or switch up the sweet berries based on your personal preference. A combination of fresh berries and frozen can be used, or all of one or the other.
  • Cornstarch. This ingredient is essential to get that gooey, jam-like consistency to the fruit layer. Without it, the filling might end up runny.
  • Lemon. You’ll want both lemon juice and lemon zest for this recipe. For the most flavor, avoid bottled juice, though. You’ll get the perfect hint of lemon and freshness.

How to Make Berry Crumble Bars

The basic steps for making these triple berry crumb bars are simple to follow:

Mix the Butter and Sugar

Preheat the oven to 375℉. This step is essential to ensure the crust cooks up uniformly.

Combine the butter, brown sugar, egg, and vanilla extract in a large mixing bowl. Use a handheld mixer to beat the ingredients on medium speed for 1 to 2 minutes. 

It should be completely mixed and slightly fluffy.

Add the Flour and Oats

Pour the dry ingredients, the flour, baking powder, and salt, into the large bowl with the butter mixture.

Mix until everything is combined.

Use a spatula to stir the oats into the flour mixture. If you use the mixer, be sure it’s on low speed. Your dough should be a little thick with coarse crumbs, especially if the butter wasn’t very soft.

Make the Berry Mixture

In another large bowl, mix the juicy berries with the cornstarch and white sugar. Gently toss until they are evenly coated.

Pour in the lemon juice and sprinkle on the lemon zest and stir again.

Don’t overwork this step or the berries will get crushed.

Cornstarch and sugar are added to the berries.

Start Building the Crumble

Cover the bottom and sides of a 9×9-inch baking pan with cooking spray or parchment paper.

Use your hands or a spatula to carefully but firmly press half of the mixture of flour and butter into the bottom of the prepared pan.

You want it evenly spread out and touching all of the sides.

Top with Berries and More Crumble

Pour the berry mixture over the crumble layer. Carefully spread the berries so they completely cover the bottom in an even layer.

Sprinkle the remaining crumble mixture over the top of the blueberries, strawberries, and blackberries. Pinch off small sections if needed.

Bake, then Rest

Place the berry crumble in the preheated oven and bake for 40 to 45 minutes. The crust will be golden brown and the berry layer should be bubbling.

Let the pan sit for at least 3 to 4 hours until it reaches room temperature. If you cut into it when it’s hot, the fruit layer won’t set up.

Please enjoy these bars within 24 hours, or the crumb topping and base will start to get soggy. Keep them in an airtight container or completely covered with plastic wrap.

Healthy, fruity, and delicious crumble bars are the best summer dessert.

Do you need to refrigerate berry crumble bars?

While you don’t need to refrigerate these bars, they will last longer in the fridge. These bars are best within 24 hours, but the fridge will help keep the shortbread layer from getting soggy.

Can I freeze crumble bars?

You can definitely freeze crumble bars! In fact, this is a great way to make them ahead of time and have them when you’re ready. For ease of use, freeze individual-sized portions between wax paper so you can pull out one serving at a time.

Berry crumble bars are full of summer flavors and easy to make.

Dietary Modifications

The recipe you’ll find below is already vegetarian as written.  Here are some adjustments and substitutions you can make to help it fit your other dietary requirements:

  • Gluten-free: Stick with a gluten-free 1-to-1 blend and ensure the oats are free of gluten.
  • Dairy-free: Opt for coconut oil or a vegan buttery stick instead of butter.
  • Sugar-free: Choose a sweetener like stevia or coconut sugar.

Expert Tips and Tricks

  • Chop the berries. Cut everything into smaller, evenly-sized pieces so they spread out and you get some in every bite.
  • Old is key. Use only old-fashioned rolled oats for the best texture.
  • Change it up. Use whatever berries you have on hand to make these easy bars.
  • You choose. You can opt for either fresh or frozen berries depending on the time of year.
  • Hurry up and wait. Be sure to let the crumble cool completely before enjoying, but then eat it within 24 hours for the best results.

What to Serve with Berry Crumble Bars

While these bars are delicious on their own, you can add a few things to make this simple recipe even better.

Top them with a scoop of vanilla ice cream or Coconut Whipped Cream for the perfect dessert.

If you’re thirsty, try a Mixed Berry Smoothie or Frozen Lemonade.

You can even whip up some Homemade Sorbet for a refreshing twist.

More Summer Dessert Recipes

When the summer months get here, it’s awesome to have some go-to desserts ready. Try any of these easy recipes next.

Piña Colada Bars are light and refreshing.

Both Homemade Peanut Butter Cups and Peanut Butter Rice Krispie Treats are the perfect way to satisfy PB-chocolate lovers.

If you’re craving something fruity, try an Apple Crisp or a Gluten-Free Peach Cobbler.

Tap stars to rate!

5 from 2 votes

Mixed Berry Crumble Bars

Sweet, buttery, and the best blend of flavors, these Berry Crumb Bars will quickly be your new favorite summer dessert. A healthy fruit mix of either fresh or frozen berries is sandwiched between shortbread layers and baked to gooey perfection.
Healthy, fruity, and delicious crumble bars are the best summer dessert.
Yield 16 servings
Prep 20 minutes
Cook 40 minutes
Total 1 hour
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  • 1 cup butter salted, room temperature
  • 1 cup brown sugar
  • 1 egg large
  • 1 tsp. vanilla
  • 2 cups flour all purpose or gluten-free
  • 2 cups oats whole, rolled, gluten-free
  • 1 tsp. baking powder
  • ¼ tsp. salt
  • 1 pint blueberries
  • 6 oz. strawberries
  • 6 oz. blackberries
  • ¼ cup cornstarch
  • ½ cup white sugar
  • 1 lemon juice and zest


  • Preheat oven to 375 degrees.
  • Add the butter, brown sugar, egg, and vanilla to a large bowl. Mix with a handheld mixer on medium speed for 1-2 minutes or until combined.
  • Add the flour, baking powder, and salt to the bowl and mix until combined.
  • Mix in the oats using either a spatula or on low speed with the mixer until everything is well incorporated. The mixture may be a little thick and crumbly at this point depending on how soft your butter was.
  • Add the berries to a separate large bowl and sprinkle with the cornstarch and sugar. Toss to combine.
  • Pour in the lemon juice and add the zest. Toss until the berries are well coated.
  • Press half of the oat crumble into the bottom of a 9×9 inch baking dish that has been sprayed with non-stick cooking spray. Spread the berries out over the crust in a single layer and then sprinkle the remaining crumble over the berries.
  • Bake in the preheated oven for 40-45 minutes or until the crust is golden brown.
  • Let rest for at least 3-4 hours or until it reaches room temperature. It’s best if served within the first 24 hours. After this time it can still be eaten for up to 2-3 days, but the crust will get more soggy.
Last step! If you make this, please leave a review letting us know how it was!

Tap stars to rate!

5 from 2 votes



Calories: 306kcal, Carbohydrates: 46g, Protein: 4g, Fat: 13g, Saturated Fat: 8g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 3g, Trans Fat: 0.5g, Cholesterol: 41mg, Sodium: 131mg, Potassium: 159mg, Fiber: 4g, Sugar: 24g, Vitamin A: 411IU, Vitamin C: 15mg, Calcium: 53mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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