Can I use frozen blueberries instead of fresh?

Absolutely! Use frozen blueberries directly from the freezer without thawing. This prevents excess moisture and helps maintain the bars' structure.

How do I know when the bars are fully baked?

Look for golden-brown edges and a bubbly filling around the sides. The center should feel set when lightly pressed, not jiggly.

Can I make these in a different pan size?

Yes, but adjust baking time accordingly. A 9x9 pan will need 5-7 minutes less baking time, while a 9x13 pan creates thinner bars that bake faster.

What's the best way to cut clean squares?

Use a sharp knife wiped clean between cuts, and ensure the bars are completely cooled. Lifting them out using the parchment paper overhang makes cutting much easier.

Can I double this recipe?

Certainly! Double all ingredients and use a 9x13 pan. Increase baking time by 10-15 minutes, checking for doneness with the same visual cues.

How can I prevent the topping from burning?

If the top browns too quickly, tent the pan with foil for the last 10-15 minutes of baking while the filling continues to cook through.

Blueberry Crumble Bars Recipe You'll Make Again and Again

Name: Blueberry Crumble Bars
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Yield: 16 Bars
Cuisine: American
Ingredients: 2 cups all-purpose flour; 1½ cups old-fashioned rolled oats; ¾ cup packed light brown sugar; ½ cup granulated sugar; 1 teaspoon vanilla extract; ½ teaspoon salt; ¾ cup cold unsalted butter, cubed; 3 cups fresh or frozen blueberries; 3 cups fresh or frozen blueberries ⅓ cup granulated sugar; 2 tablespoons cornstarch; 1 tablespoon fresh lemon juice; 1 teaspoon lemon zest

Description

Blueberry Crumble Bars are an irresistible dessert with juicy blueberries and a buttery crumb topping that everyone will love.

Ingredients

Scale

For the Base and Topping:

2 cups all-purpose flour
1½ cups old-fashioned rolled oats
¾ cup packed light brown sugar
½ cup granulated sugar
1 teaspoon vanilla extract
½ teaspoon salt
¾ cup cold unsalted butter, cubed

For the Blueberry Filling:

3 cups fresh or frozen blueberries
⅓ cup granulated sugar
2 tablespoons cornstarch
1 tablespoon fresh lemon juice
1 teaspoon lemon zest

Substitution Options:

Gluten-free: Replace all-purpose flour with a 1:1 gluten-free flour blend
Dairy-free: Substitute cold vegan butter or coconut oil for regular butter
Vegan: Use plant-based butter and ensure your sugar is vegan-friendly
Lower sugar: Reduce sugar by ¼ cup in both base and filling

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Instructions

Prep the Pan
Preheat oven to 350°F (175°C). Line an 8×8-inch pan with parchment and lightly grease.
Make the Blueberry Filling
Mix blueberries, sugar, cornstarch, lemon juice, and zest in a bowl. Set aside.
Make the Crumble
Combine flour, oats, sugars, vanilla, and salt. Cut in cold butter until crumbly.
Assemble
Press ⅔ of the crumble into the pan. Spread blueberry filling on top, then sprinkle with remaining crumble.
Bake
Bake 40–45 minutes until golden and bubbly.
Cool & Slice
Cool completely (about 2 hours) before cutting into bars.

Prep Time: 15m
Cook Time: 45m
Category: Dessert
Cuisine: American

Nutrition

Calories: 185 calorie