Blackberry Crumb Bars

These buttery blackberry crumb bars are made with brown sugar, vanilla, and fresh blackberries. An easy dessert bar recipe for summer!

Blackberry crumb bars are such a delightful way to enjoy the juicy, sweet-tart flavor of blackberries in a simple yet delicious dessert. With a buttery base, a generous layer of fresh blackberries, and a crisp, crumbly topping, these bars are perfect for any occasion. Keep things simple by serving them as they are or top with ice cream for an indulgent treat!

Why You’ll Love This Blackberry Crumb Bars Recipe

• Simple ingredients. This recipe uses basic pantry staples plus fresh blackberries, making it an easy recipe that doesn’t require hunting down specialty ingredients.
• Easy preparation. With straightforward steps and minimal equipment required, this recipe is perfect for bakers of all skill levels.
• Flavorful. The combination of a buttery, tender base, juicy blackberries, and a crisp, crumbly topping creates a delightful texture and flavor contrast in every bite.
• Crowd-pleaser. These bars are perfect for most any occasion, from family gatherings to potlucks, and they’re sure to impress your guests.

What You’ll Need

See the recipe card below for the full recipe, including ingredient quantities and complete instructions.

• Unsalted butter – You’ll need both melted and softened butter here – the former for the crumb and the latter for the batter.
• All-purpose flour – There’s flour in both the cake and the crumb, too. Be sure to measure by weight or use the spoon and sweep method for accuracy. Learn more: How to Measure Flour
• Brown sugar – I like light brown sugar here for its milder flavor. You can use dark brown sugar if you want a more pronounced molasses flavor.
• Salt
• Baking powder
• Confectioners’ sugar – Also labeled as powdered sugar or 10X sugar.
• Vanilla extract
• Eggs – Let these come to room temperature for easier mixing.
• Blackberries – I recommend using fresh blackberries if you have access to them. See my note below about using frozen berries.

Can I Use Frozen Blackberries?

While I prefer fresh berries whenever possible, you can use frozen if that’s what you have. To substitute frozen blackberries in this recipe, first thaw the berries in a colander over a bowl to catch excess liquid. Allow them to drain thoroughly to prevent additional moisture from affecting the texture of the bars. Frozen blackberries can be more tart than fresh ones, so you may want to taste the berries and add a tablespoon or two of sugar if needed. Incorporate the drained berries as directed, and be prepared to extend the baking time by a few minutes if necessary, checking for a golden top and a toothpick that comes out with moist crumbs but no wet batter. This ensures your crumb bars turn out perfectly with frozen berries.

How to Make Blackberry Crumb Bars

• Prepare for baking. Heat the oven to 350°F. Grease and line an 8-inch square baking pan, and then grease and flour the parchment paper.
• Make the crumb topping. Combine the melted butter, brown sugar, and 1/4 teaspoon salt. Mix in a cup of flour until crumbs form. Refrigerate while you make the batter.

• Mix the batter. Whisk together the remaining flour, baking powder, and remaining salt. In a separate bowl, beat the softened butter, confectioners’ sugar, and vanilla until light and fluffy. Mix in the eggs one at a time. Then, mix in the flour mixture just until combined.
• Assemble. Spread the batter in the prepared pan, top with blackberries, and sprinkle with the chilled crumb topping.

• Bake. Place the pan in the heated oven, and bake 40 to 45 minutes. The bars should be golden brown, and a pick inserted into the center should come out with moist crumbs attached.
• Cool. Place the pan on a wire rack and allow to cool completely before cutting into bars.

Variations and Serving Suggestions

• Mixed berries. Use a mixture of your favorite berries instead of just blackberries.
• Nutty crumble. Add about 1/2 cup of chopped nuts (like pecans, almonds, or walnuts) to the crumb topping for a bit of crunch and added flavor.
• Citrus twist. Add 1 tablespoon of lemon or lime juice and 1 teaspoon of zest to the batter for a refreshing citrus note that pairs well with the blackberries.
• Ice cream. Pair these blackberry bars with a scoop of vanilla ice cream.
• Whipped cream. Serve your bars with a dollop of freshly whipped cream for an extra touch of indulgence.
• Confectioners’ sugar. Dust the bars with confectioners’ sugar just before serving.

How to Store

Store your blackberry crumb bars in an airtight container at room temperature for up to 3 days or refrigerate for up to a week.

Can These Blackberry Bars Be Frozen?

Yes! To freeze your blackberry crumb bars, first make sure they’re completely cooled. Then arrange the cut bars in a single layer on a baking sheet. Place the sheet in the freezer for about an hour to firm up. After that, transfer the bars to an airtight container or freezer-safe bag, separating layers with parchment paper to prevent sticking. I prefer to wrap the bars individually in plastic wrap before placing in a container. Label the container with the date and freeze for up to 3 months. When ready to enjoy, thaw the bars at room temperature for a few hours or overnight in the refrigerator.

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