Honestly, these Blueberry Crumble Bars have become a staple in our house, especially during the summer months when blueberries are at their peak. There’s just something so comforting and satisfying about that buttery, crumbly topping paired with the burst of sweet and slightly tart blueberries underneath. The first time I made them, my family devoured them in a single afternoon, and requests for them have been constant ever since! They’re incredibly easy to whip up, making them perfect for a last-minute dessert or a potluck contribution. The combination of textures – the crisp crumble, the tender base, and the juicy blueberries – is simply irresistible. If you’re looking for a crowd-pleasing dessert that’s both rustic and refined, look no further. These Buttery & Crunchy Blueberry Crumble Bars are guaranteed to be a hit.

Ingredients

For the Crust and Crumble Topping:

• 2 cups all-purpose flour
• 1 cup (2 sticks) cold unsalted butter, cut into small cubes
• ¾ cup granulated sugar
• ½ cup packed light brown sugar
• ½ teaspoon baking powder
• ¼ teaspoon salt
• 1 teaspoon vanilla extract
• ½ cup rolled oats (old-fashioned or quick-cooking) – for extra crunch and texture
• ½ cup chopped pecans or walnuts (optional, for added nutty flavor and crunch) – can be omitted for nut-free version

For the Blueberry Filling:

• 6 cups fresh blueberries (or frozen, see notes below) – fresh blueberries are best for vibrant flavor and texture
• ¼ cup granulated sugar
• 3 tablespoons cornstarch – to thicken the blueberry juices and prevent a soggy bottom
• 1 tablespoon lemon juice – enhances the blueberry flavor and adds a touch of brightness
• ½ teaspoon ground cinnamon (optional, for a warm spice note) – adds depth of flavor but can be skipped if preferred

Ingredient Notes & Substitutions:

• Butter: Unsalted butter is recommended to control the salt content. If using salted butter, omit the ¼ teaspoon of salt in the crust/crumble. Ensure the butter is very cold for the best crumble texture.
• Flour: All-purpose flour works perfectly for this recipe. For a slightly denser and nuttier flavor, you can substitute up to ½ cup of all-purpose flour with whole wheat pastry flour. For gluten-free options, see the FAQ section.
• Sugars: The combination of granulated and brown sugar provides both sweetness and moisture. Light brown sugar is preferred for its subtle molasses flavor, but dark brown sugar can also be used for a richer taste. You can adjust the sugar levels slightly to your preference, especially depending on the sweetness of your blueberries.
• Blueberries: Fresh blueberries are ideal when in season for their vibrant flavor and texture. Frozen blueberries can also be used, but it’s recommended to thaw them slightly and drain off any excess liquid before using to prevent the bars from becoming too watery. If using frozen, you might need to increase the cornstarch slightly to compensate for the extra moisture. Wild blueberries will offer a more intense blueberry flavor.
• Lemon Juice: Freshly squeezed lemon juice is always best, but bottled lemon juice can be used in a pinch. Lime juice can also be substituted for a slightly different citrus note.
• Nuts: Pecans and walnuts add a lovely nutty flavor and extra crunch to the crumble. Feel free to use your favorite nuts, such as almonds or hazelnuts, or omit them altogether for a nut-free version. Toasted nuts will enhance their flavor even further.
• Spices: Cinnamon is a classic pairing with blueberries, but you can also experiment with other warm spices like nutmeg, cardamom, or ginger. A pinch of lemon zest in the crumble can also add a bright citrus note.
• Oats: Rolled oats (both old-fashioned and quick-cooking) work well in the crumble. They add texture and a slightly nutty flavor. If you don’t have oats, you can substitute them with more flour or finely chopped nuts.

Instructions

Get Started:

1. Preheat the Oven and Prepare Pan: Preheat your oven to 375°F (190°C). Grease and lightly flour a 9×13 inch baking pan. Alternatively, line the pan with parchment paper, leaving an overhang on the sides for easy removal of the bars later. This parchment paper sling method is highly recommended for clean cuts and easy serving.

Make the Crust and Crumble Topping:

1. Combine Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking powder, and salt. This ensures the baking powder and salt are evenly distributed throughout the dry ingredients, leading to a more consistent texture.
2. Cut in the Cold Butter: Add the cold, cubed butter to the dry ingredients. Using a pastry blender, your fingertips, or a food processor, cut the butter into the flour mixture until it resembles coarse crumbs with some pea-sized pieces of butter remaining. The key here is to keep the butter cold. Cold butter creates pockets of air in the dough as it melts during baking, resulting in a flaky and crumbly texture. If using your fingertips, work quickly to prevent the butter from warming up too much. If using a food processor, pulse in short bursts to avoid over-processing.
3. Add Vanilla and Oats (and Nuts, if using): Stir in the vanilla extract and rolled oats (and chopped nuts, if using). Mix until just combined. The oats and nuts add fantastic texture and flavor to the crumble topping.
4. Divide for Crust and Crumble: Press approximately two-thirds of the crumble mixture evenly into the prepared baking pan to form the crust. Use the back of a measuring cup or your fingers to firmly press the mixture into an even layer covering the bottom of the pan. Pressing the crust firmly will ensure it holds its shape and doesn’t become too crumbly during baking. Set the remaining crumble mixture aside for the topping.

Prepare the Blueberry Filling:

1. Combine Filling Ingredients: In a separate large bowl, gently toss together the fresh blueberries, granulated sugar, cornstarch, lemon juice, and cinnamon (if using). Coating the blueberries in cornstarch helps to thicken their juices during baking, preventing the bars from becoming soggy. Lemon juice enhances the blueberry flavor and adds brightness. Be gentle when tossing to avoid bruising the blueberries.

Assemble and Bake:

1. Pour Filling over Crust: Pour the blueberry filling evenly over the prepared crust in the baking pan. Spread it out to the edges to ensure even blueberry distribution in every bar.
2. Sprinkle Crumble Topping: Sprinkle the reserved crumble topping evenly over the blueberry filling. Distribute the crumble topping generously to get that satisfying buttery and crunchy layer in every bite.
3. Bake: Bake in the preheated oven for 45-55 minutes, or until the crumble topping is golden brown and the blueberry filling is bubbly. The baking time may vary slightly depending on your oven. The bars are done when the topping is nicely browned and the blueberry juices are bubbling around the edges. If the topping starts to brown too quickly, you can loosely tent the pan with aluminum foil for the last 10-15 minutes of baking to prevent it from burning.
4. Cool Completely: Remove the blueberry crumble bars from the oven and let them cool completely in the pan on a wire rack before cutting into squares or bars. Cooling completely is crucial for the bars to set properly and for easier cutting. Warm bars will be softer and more difficult to cut neatly. This cooling process can take at least 2-3 hours, or even overnight for best results.

Cutting and Serving:

1. Cut into Bars: Once completely cooled, cut the blueberry crumble bars into squares or bars of your desired size. If you used parchment paper overhang, lift the bars out of the pan using the parchment paper sling and then cut them. This makes cutting much easier and cleaner.

Nutrition Facts (Approximate)

(Note: Nutritional information is an estimate and can vary based on specific ingredients and serving size. It’s always best to use a nutrition calculator for precise values.)

Serving Size: Approximately 1 bar (assuming recipe is cut into 16 bars)
Calories per Serving: Approximately 300-350 calories

• Fat: 15-20g
• Saturated Fat: 9-12g
• Cholesterol: 40-50mg

Disclaimer: These are approximate values. For accurate nutritional information, use a nutrition calculator with the specific brands and quantities of ingredients you use.

Preparation Time

Prep Time: 20-25 minutes
Bake Time: 45-55 minutes
Cooling Time: 2-3 hours (minimum, or overnight for best results)
Total Time (Approximate): 3-4 hours (including cooling)

• Active time (hands-on time) is relatively short, making this a great recipe for busy bakers. Most of the time is passive cooling time.

How to Serve Buttery & Crunchy Blueberry Crumble Bars

These blueberry crumble bars are incredibly versatile and can be enjoyed in numerous ways. Here are some serving suggestions:

• Warm:
  • Slightly Warmed: Gently reheat a bar in the microwave for a few seconds or in a low oven to bring out the warm blueberry flavors and soften the crumble slightly.
  • With Ice Cream: Serve warm bars topped with a scoop of vanilla ice cream, blueberry ice cream, or even a tangy lemon sorbet. The contrast of warm crumble and cold ice cream is heavenly.
  • With Whipped Cream: A dollop of freshly whipped cream or whipped coconut cream (for a dairy-free option) adds a touch of elegance and creaminess.
  • With Custard: A warm vanilla custard or crème anglaise drizzled over warm bars is a decadent treat.
• Cold:
  • Straight from the Fridge: Cold bars are perfect for grab-and-go snacks or desserts, especially on a hot day. The crumble firms up beautifully when chilled.
  • Picnic Perfect: These bars are ideal for picnics and potlucks as they travel well and hold their shape.
  • Lunchbox Treat: Pack a cold bar in a lunchbox for a delightful midday treat.
• Toppings & Garnishes:
  • Dusting of Powdered Sugar: A simple dusting of powdered sugar adds a touch of sweetness and visual appeal.
  • Lemon Zest: A sprinkle of fresh lemon zest enhances the citrus notes and adds a burst of fresh flavor.
  • Fresh Berries: Garnish with extra fresh blueberries, raspberries, or strawberries for a beautiful and flavorful presentation.
  • Caramel Sauce: A drizzle of salted caramel sauce adds a layer of rich sweetness and salty-sweet contrast.
  • Maple Syrup: A light drizzle of maple syrup complements the blueberry flavor and adds a hint of warmth.
  • Chopped Nuts: Sprinkle with extra chopped pecans or walnuts for added crunch and nutty flavor.

Additional Tips for Perfect Buttery & Crunchy Blueberry Crumble Bars

1. Keep the Butter Cold: This is the golden rule for achieving a truly crumbly and buttery texture. Cold butter prevents the gluten in the flour from developing too much, resulting in tenderness. Work quickly when cutting in the butter and avoid over-mixing the dough. If your kitchen is warm, you can even chill the dry ingredients and bowl before starting.
2. Don’t Overmix the Crumble: Mix the crumble ingredients just until combined. Overmixing will develop the gluten and result in a tougher, less crumbly topping. Stop mixing as soon as the mixture resembles coarse crumbs.
3. Press the Crust Firmly: Pressing the crust firmly into the pan is important for it to hold its shape and prevent it from being too crumbly or falling apart when you cut the bars. Use the back of a measuring cup or your fingers to create an even and compact layer.
4. Thaw Frozen Blueberries (Slightly): If using frozen blueberries, thaw them slightly and drain off any excess liquid before using. This will prevent the bars from becoming too watery and soggy. You might also need to increase the cornstarch by a teaspoon or two to compensate for any remaining moisture.
5. Cool Completely Before Cutting: Patience is key! Allow the blueberry crumble bars to cool completely in the pan before cutting. This allows the bars to set properly and makes them much easier to cut into clean, neat squares or bars. Warm bars will be soft and prone to crumbling. For the cleanest cuts, chill the bars in the refrigerator for an hour or two after they have cooled to room temperature.

Frequently Asked Questions (FAQ)

Q1: Can I use frozen blueberries instead of fresh?
A: Yes, you can definitely use frozen blueberries! However, it’s important to thaw them slightly and drain off any excess liquid before using. This will help prevent the bars from becoming too watery. You might also consider increasing the cornstarch in the filling by about a teaspoon to help thicken the juices further.

Q2: Can I make these bars ahead of time?
A: Absolutely! Blueberry crumble bars are a great make-ahead dessert. You can bake them a day or two in advance and store them at room temperature in an airtight container. For longer storage, you can refrigerate them for up to 5 days. In fact, many people find they taste even better the next day after the flavors have had time to meld.

Q3: Can I freeze blueberry crumble bars?
A: Yes, these bars freeze beautifully! Allow them to cool completely, then cut them into bars. Wrap each bar individually in plastic wrap, then place them in a freezer-safe bag or container. They can be frozen for up to 2-3 months. To thaw, simply unwrap and let them thaw at room temperature for about 30-60 minutes, or overnight in the refrigerator. You can also gently reheat them in a low oven if desired.

Q4: Can I make these bars gluten-free?
A: Yes, you can easily make gluten-free blueberry crumble bars! Simply substitute the all-purpose flour in the crust and crumble topping with a gluten-free all-purpose flour blend. Ensure the blend is designed for baking and contains xanthan gum or guar gum (or add a pinch if it doesn’t). Bob’s Red Mill Gluten-Free 1-to-1 Baking Flour or King Arthur Baking Company Gluten-Free Measure for Measure Flour are good options. The rest of the ingredients are naturally gluten-free.

Q5: Can I use a different type of berry?
A: Yes, you can definitely experiment with other berries! Raspberries, blackberries, mixed berries, or even sliced strawberries would all work wonderfully in this recipe. Adjust the sugar level slightly depending on the sweetness of the berries you choose. For tart berries like raspberries or blackberries, you might want to keep the sugar amount as is, or even increase it slightly if you prefer a sweeter dessert.

Print