Yield: 16 bars
Prep Time: 20 minutes
Bake Time: 45–50 minutes

Ingredients

Crust & Crumble

• 2½ cups (315 g) all-purpose flour
• 1 cup (200 g) granulated sugar
• ½ tsp salt
• 1 tsp baking powder
• 1 cup (225 g) cold unsalted butter, cubed
• 1 large egg
• 1 tsp vanilla extract

Blueberry Filling

• 4 cups (600 g) fresh or frozen blueberries
• ⅓ cup (65 g) granulated sugar
• 2 tbsp cornstarch
• 1 tbsp lemon juice
• 1 tsp lemon zest (optional)
• 1 tsp vanilla extract

Instructions

1. Preheat oven to 350°F (175°C).
2. Grease or line a 9×13-inch baking pan with parchment paper.
3. In a large bowl, whisk together flour, sugar, salt, and baking powder.
4. Cut in the cold butter using a pastry cutter or your fingertips until the mixture resembles coarse crumbs.
5. Mix the egg and vanilla together, then stir into the crumb mixture until it just comes together.
6. Press two-thirds of the mixture firmly into the prepared pan.
7. In another bowl, gently toss blueberries with sugar, cornstarch, lemon juice, zest, and vanilla.
8. Spread the blueberry mixture evenly over the crust.
9. Sprinkle the remaining crumb mixture over the blueberries.
10. Bake for 45–50 minutes, until the topping is lightly golden and the filling is bubbling.
11. Cool completely (2–3 hours), then refrigerate for at least 1 hour before slicing for clean bars.

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Nut Information

This recipe contains no nuts in the ingredient list.

However:

• Always check packaged ingredients (especially vanilla extract and baking powder) if serving someone with a severe nut allergy.
• If using frozen berries from a processing facility, verify whether they were packed in a nut-free facility if cross-contact is a concern.

Optional Nut Additions (if no allergies)

• ½ cup chopped pecans
• ½ cup sliced almonds
• ½ cup chopped walnuts

Mix them into the crumble topping before baking for extra crunch.

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Storage

• Room temperature: Up to 2 days in an airtight container.
• Refrigerator: Up to 5 days.
• Freezer: Up to 3 months. Wrap individual bars and thaw overnight in the refrigerator.

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Tips

• Frozen blueberries work well—do not thaw before using.
• Chill before cutting to prevent the filling from oozing.
• Use parchment paper with overhang for easy removal.
• For extra crunch, sprinkle 2 tablespoons coarse sugar over the crumble before baking.

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Nutrition (Approximate, per bar)

• Calories: 240
• Carbohydrates: 34 g
• Protein: 3 g
• Fat: 11 g
• Saturated Fat: 7 g
• Fiber: 2 g
• Sugar: 16 g
• Sodium: 90 mg

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Q&A

Q: Can I use frozen blueberries?
Yes. Use them straight from the freezer without thawing.

Q: Why did my bars turn out runny?
They likely needed more cooling time. The filling sets as it cools. Also, be sure to use the full amount of cornstarch.

Q: Can I make these gluten-free?
Yes. Substitute a 1:1 gluten-free baking flour blend.

Q: Can I reduce the sugar?
Yes. Reduce the sugar in the filling to ¼ cup if your berries are naturally sweet.

Q: How do I get neat slices?
Refrigerate the bars for at least 1 hour after they’ve cooled, then cut with a sharp knife wiped clean between slices.

Q: Can I use other berries?
Absolutely. Raspberries, blackberries, cherries, or a mixed berry blend all work well with the same method.

Q: Can I make these ahead of time?
Yes. They actually taste even better the next day after the flavors have melded and the filling has fully set.