Blackberry Crumble Bars

blackberry crumble bar

With school back in session and the days getting cooler, summer’s becoming a distant memory. The good news is that this also signals the beginning of baking season (for me, anyway).  With the warm, tart taste of summer’s wild blackberries still lingering in our heads, I thought these blackberry/oatmeal/walnut crumble bars would make the perfect back-to-school treat. Summer sandwiched between layers of fall.

If you’re lucky, you have a few bags of wild blackberries stashed in the freezer, and/or a pantry filled with homemade jam. But for the rest of us, there’s the grocery store (or Mom or Aunt Kelley – hint hint).  These frozen blackberries from Oregon worked very well.

frozen blackberries


Blackberry Crumble Bars

Makes 24 bars

  • 8-10 oz frozen blackberries, thawed and drained
  • 1 cup (8 oz) blackberry jam or preserves
  • 2 ½ cups flour
  • 2/3 cup granulated (white) sugar
  • ½ teaspoon salt
  • 1 cup (2 sticks) plus 2 tablespoons unsalted butter, softened
  • 1/3 cup brown sugar (packed)
  • ½ cup quick-cooking oats
  • ½ cup chopped walnuts

Heat oven to 375F. Line a 9” x 13” pan with foil. (You’ll thank me for this later.)


In a small bowl combine thawed blackberries and jam. Mash the berries a little so that the mixture looks like chunky jam.


To the bowl of a food processor add flour, granulated sugar, salt and 1 cup softened butter; pulse to combine. (You could also use a stand mixer or mix by hand.)



Scatter half of the flour mixture into the prepared pan and press to form an even crust. Bake for 15 minutes.



While crust is baking, make crumble topping:

Mix together remaining flour mixture, brown sugar, oats, walnuts and remaining 2 tablespoons butter until incorporated. (I find fingers work best for this.)IMG_3932


Crumble topping ready to go.

Crumble topping ready to go.

After 15 minutes, remove pan from oven and pour/spread blackberry mixture evenly over the crust layer.


Sprinkle oats/walnut crumble mixture over the berry layer. (No need to press down.) IMG_3940

Bake for 25 minutes, or until crumble top is nicely browned. Let cool before removing foil from pan and slicing into bars.

After cooling, the whole thing lifts right out of the pan.

After cooling, the whole thing lifts right out of the pan.


Like most baked goods, these are best the same day they’re baked.  However, they’ll keep for several days at room temperature and also freeze well.


Cut the bars smaller to feed a crowd.


Top-secret patch of wild blackberries (Hood Canal, WA, July)


A Block Island summer snack

A Block Island summer snack (RI, August)


My dad showing off his crop of cultivated Cascade berries. (WA, July)


10 thoughts on “Blackberry Crumble Bars

  1. These look absolutely delectable. Great shot of the “real” wild blackberries on Hood Canal.
    Your recipes are always inspiring.

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