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Brown Butter Mixed Berry Crumble Bars are sweet, buttery, and so good you’ll want to keep them all to yourself! There’s a brown butter shortbread crust with a brown butter crumble on top. The filling consists of raspberry preserves, blackberries, blueberries, and strawberries – bursting with delicious mixed berry flavor!
After you make these crumb bars, give my blueberry cobbler a try too!

mixed berry crumble bars
Barries are coming back in season, the weather’s warming, the sun’s out longer -it’s great. These Brown Butter Mixed Berry Crumble Bars are a great way to welcome berry season. They’re such a sweet treat. Bursting berries in every bite with a yummy brown butter crumble on top with a brown butter short bread crust – you really can’t go wrong. Just like with my tried and true Bakery Style Blueberry Muffins and Strawberry Rose Streusel, these bars are sure to be a crowd pleaser!
Head to the store, pick up the freshest berries you can find and make these Mixed Berry Crumble Bars!

how do you make brown butter mixed berry crumble bars?
So, if you’ve made my Brown Butter Coffee Cake with Cinnamon Swirl, this is a bit similar as far as the baking process goes. You brown the butter, make the crumble topping and put it in the freezer until ready to use. Then make the shortbread crust and bake for about 20 minutes in the oven. While the shortbread crust is baking, add raspberry preserves, blackberries, strawberries, and blueberries to a sauce pan and bring to a boil.
Boil the berries for about 15 minutes, until the berries become soft. Mix together a little bit of the berry sauce with 2 tbsps of corn starch in a small bowl and add corn starch slurry to berry sauce and stir together. Remove from heat and allow to cool for about 5 minutes. Sauce should thicken a little.
Once all of that is done, add the berry sauce on top of the shortbread crust and then top with the brown butter crumble. Bake for 45 minutes.
(Almost done) – this is the most important step. Once the Mixed Berry Crumble Bars are removed from the oven, they are not done yet! You must allow them to cool and set. Let the bars cool for about an hour and then set in the refrigerator for 2 hours. Yes Yes, I know it’s a long time but it’s so worth it.

what ingredients do I need?
For this recipe, you’ll need:
- 3 sticks of salted butter – you can use unsalted butter
- sugar
- brown sugar
- all-purpose flour
- vanilla extract
- Raspberry Preserves
- Blueberries, Strawberries, Blackberries
- Corn Starch
- a lemon
Simple, wholesome ingredients for these Brown Butter Mixed Berry Crumble Bars!

what sort of cooking equipment do i need?
You don’t need too much for this recipe. Just a few basics will do just fine!
- 8×8 square baking dish
- small sauce pan
- a few mixing bowls
- parchment paper

how do you brown butter?
If you haven’t had browned butter, it’s truly a treat. Also, super easy to make. Simply add butter to a sauce pan or skillet over low heat. (PRO TIP: Use a lightly colored pan/skillet so that you can see when the butter turns brown. It’s more difficult to tell on a dark pan/skillet.) Stir occasionally. When butter becomes foamy and foam begins to brown, remove from the heat and allow to cool.
Once the foam disappears, there should be little brown bits on the bottom of the pan. That’s how you know it’s successfully browned! I like to keep the little brown bits, I think it adds flavor. However, you can choose to strain out the little bits. Up to you!

Can I use frozen berries?
You absolutely can use frozen berries, however, I highly recommend using fresh berries. A frozen mixed berry blend has a lot more water and will take a bit longer on the stove to cook down and make into a sauce/compote. Also, in my opinion, the fresh berries are a bit sweeter because they’re ripe. You just never know how ripe the frozen berries are when they pick them to freeze, so fresh is always my recommendation.

more recipes that I’m loving!
Brown Butter Mixed Berry Crumble Bars

Equipment
- Skillet
- 8×8 Baking Pan
Ingredients
Crumble Topping
- 1/2 cup salted butter
- 1 cup All-Purpose Flour
- 1 cup Brown Sugar
- 1/2 tsp Kosher Salt
Shortbread Crust
- 2 sticks salted butter
- 1/2 cup Brown Sugar
- 1/4 tsp Kosher Salt
- 1 tsp Vanilla Extract
- 2 1/2 cups All-Purpose Flour
Mixed Berry Filling
- 1 cup Raspberry Preserves
- 1/2 cup Fresh Blueberries
- 8 Fresh Strawberries, (sliced)
- 1/4 cup Fresh Blackberries
- 1/2 lemon, (squeezed)
- 2 tbsps Corn Starch
Instructions
- Preheat oven to 350 degrees °F.
- Add 3 sticks of butter to a skillet or pan and brown over low heat. Reserve one cup of the brown butter to the shortbread crust and reserve the remaining amount for the crumble topping.
- Start by making the crumble topping. In a bowl, add 1/2 cup of browned butter, all purpose flour, brown sugar, and kosher salt. Toss together with your fingers until clumps begin to form. Add to the freezer until ready to use.
- Now let’s make the crust. Add 1 cup of the brown butter to a large bowl. Add brown sugar, kosher salt, vanilla extract, and all purpose flour. Mix together until a dough forms. Line an 8×8 baking dish with parchment paper and place dough onto the bottom, pressing it firmly into each corner and ensuring it is spread evenly throughout the dish. Bake for 20 minutes.
- Add raspberry preserves, blueberries, sliced strawberries, blackberries, and 1/2 lemon squeezed into a sauce pan over medium low heat. Bring to a boil and simmer for 15 minutes. In a small bowl, add corn starch and a few tablespoons of the berry mixture and stir together to form a thick paste. Add to the berry sauce and remove from heat to cool slightly and thicken.
- Pour berry sauce on top of shortbread crust in the 8×8 baking dish. Remove crumble topping from freezer and generously pour on top of berry sauce, ensuring everything is covered. Bake for 45 minutes.
- Once the bars are finished baking, allow them to cool for at least an hour, then refrigerate for 2 hours.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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These got devoured by my husband and his family. I’m actually vegan but don’t have to worry about tasting any of your recipes, they are always amazing and a crowd pleaser. Some times I make something for my husband to take to work but he ends up only taking a few because he wants it all to himself 😂
Awww Thank you! That makes my day!!
Amazing recipe I’ve made these multiple times in the past year. Always a hit.
Just after making a large batch and wondering: Are they suitable for freezing?
Hi Tom! I’m so glad to hear that! Yes, these freeze really well. When you’re ready to thaw them, I recommend placing in the refrigerator as opposed to allowing them to sit out at room temperature to prevent them from becoming soggy.