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Blackberry Crumble Jam Bars with Oat Streusel

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Sweet and incredibly delicious, these blackberry jam bars, or crumble bars, are made even more perfect with an easy oat streusel. Super easy and delicious with a handful of pantry ingredients.

Blackberry Jam Bars cut into squares

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I mentioned delicious, right? They absolutely fly off the counter when I make them.

Use your favorite jam for these oh-so-perfect dessert cookie bars. Perfect all year long, in every season. 

Blackberry Crumble Jam Bars

These crumble jam bars have a sturdy, oatmeal-cookie-like base and a streusel-like topping made from the same dough. In between these sweet and delicious layers is a gooey layer of jam.

We used blackberry jam, because I’m craving all things blackberry this year, but any jam you love would be yummy. I love the contrast of a darker-hued jam; plum, blueberry, black raspberry, or even fig would be beautiful too. 

The Jam Bars Crust

The crust is sturdy and oh-so-delicious and is made with the usual:

  • Rolled old fashioned oats
  • All purpose flour
  • Brown sugar
  • Butter

The Jam Bars Filling

The filling couldn’t be easier. Much like my favorite afternoon tea jam tarts, the filling is simply a fruit jam of your choosing. As I mentioned before, I love a darker-hued jam, but anything works great. 

If the jam is tightly gelled, warm in the microwave for a few seconds to make it easier to spread. 

What I Love About These Bars

  • Um… easy, easy, easy.
  • A cookie-like crust that holds up well to cutting.
  • Perfect for packable lunches … and yes, picnics too!
  • Or making for church potlucks, block parties, office parties… or the friend who needs sweet encouragement.
Squares of Blackberry Crumble Jam Bars

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Blackberry Jam Bars cut into squares

Blackberry Crumble Jam Bars with Oat Streusel

Yield: 24 servings
Prep Time: 15 minutes
Cook Time: 37 minutes
Total Time: 52 minutes

Sweet and incredibly delicious, these blackberry jam bars, or crumble bars, are made even more perfect with an easy oat streusel.


  • 2 cups old fashioned oats
  • 2 cups all-purpose flour
  • 1 1/2 cup packed brown sugar
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 1 1/2 cups butter (24 tablespoons/ 3 sticks), diced
  • 4 tablespoons milk
  • 1 teaspoon vanilla
  • 1 1/2 - 2 cups blackberry jam*


  1. Preheat the oven to 350 degrees and line a 9×13 inch baking pan with parchment paper. Set aside.
  2. Making the Crust: Mix the oats, flour, brown sugar, baking powder, and salt in a large bowl. Using a pastry blender, a fork, or two knives, cut cold butter into flour mixture until it has a sandy texture and forms fine crumbs. Stir in the milk and vanilla until crumbs are moistened. Press two-thirds of the crumble into the bottom of the prepared baking pan. Bake for 12 minutes.
  3. Baking the Jam Bars: Remove the crust from the oven and spread the jam over the top. If necessary, warm the jam in the microwave until it is spreadable. Sprinkle the remaining 1/3 streusel over the top of the jam layer; bake for another 25-30 minutes or until the crust is lightly golden brown.
  4. Cooling: Remove the bars from the oven and cool completely before cutting. Because I can be a tad impatient — and my guys will devour them too soon, I like to refrigerate the bars until they become solid enough to cut. But… if you’re like me and can’t wait, sometimes, they’re kind of good warm too. Add some melty vanilla ice cream for an extra special treat. Otherwise, cut into 9 squares when cooled.


Food Processor:

A food processor makes it easy to cut the butter into the flour mixture. For a more tender crust, use short pulses being careful not to overprocess.


I've baked these bars using blackberry jam, but any jam you prefer can be substituted.

Nutrition Information:
Yield: 24 Serving Size: 1
Amount Per Serving: Calories: 276Total Fat: 12gSaturated Fat: 7gTrans Fat: 0gUnsaturated Fat: 4gCholesterol: 31mgSodium: 124mgCarbohydrates: 41gFiber: 1gSugar: 25gProtein: 2g

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    1. I have blackberries on my mind right now too! I’m so glad you liked it and that it worked well as a half recipe!

  1. The recipe says 3 sticks of butterr (12 tablespoons). However three sticks is 24 tablespoons. Do i need to use 3 sticks orr 1 and a half sticks?

    1. Yes, it is 3 sticks of butter — I’ve updated the recipe to be more clear. Thank you so much!

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