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Easy homemade blueberry oatmeal bars – juicy, jammy, and crunchy
Maria Canilssom

Easy Blueberry Oatmeal Bars

These Easy Blueberry Oatmeal Bars are the ultimate fuss-free treat! A single oat mixture forms the buttery crust and crunchy crumble topping for a vibrant, jammy lemon-blueberry filling. Ready in under an hour with just 7 ingredients. If you love simple fruit desserts, you'll also adore our Bakery-Style Cranberry Orange Muffins or our Vegan Ginger Pear Crisp.
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Prep Time 10 minutes
Cook Time 40 minutes
Total Time 50 minutes
Servings: 16 bars
Course: Breakfast, Dessert, Snack
Cuisine: American
Calories: 191
Ingredients Equipment Method Notes

Ingredients
  

  • 140 grams all-purpose flour (1 cup)
  • 144 grams rolled oats (1.5 cups)
  • 140 grams granulated sugar (⅔ cup)
  • 150 grams unsalted butter, melted and cooled (⅔ cup)
  • 300 grams blueberries, fresh or frozen (2 cups)
  • 50 grams granulated sugar (¼ cup)
  • 2 tsp cornstarch
  • 1 tbsp fresh lemon juice
  • 1.5 tsp lemon zest

Equipment

  • 8-inch Square Baking Pan Essential for the right bar thickness.
  • Medium Mixing Bowls For the dough and the filling.

Method
 

  1. Preheat oven to 350°F (177°C). Line an 8-inch square baking pan with parchment paper.
  2. In a medium bowl, stir together the flour, rolled oats, and ⅔ cup sugar. Pour in the melted, cooled butter and mix until a crumbly dough forms.
  3. Set aside ⅓ of the oat mixture (about 190g) for the topping. Firmly press the remaining ⅔ of the mixture into the bottom of the prepared pan to create an even crust.
  4. In another bowl, gently toss the blueberries with ¼ cup sugar, cornstarch, lemon juice, and lemon zest until evenly coated.
  5. Spread the blueberry mixture evenly over the crust. Crumble the reserved oat mixture over the top.
  6. Bake for 38-40 minutes, until the topping is golden brown and the blueberry filling is bubbling at the edges. Let cool completely in the pan on a wire rack before slicing into bars.

Notes

Pro Tips: For the crispiest crumble topping, press the reserved dough into small clumps with your fingers before sprinkling it over the blueberries. The most important step for clean slices is to let the baked bars cool completely in the pan before cutting. This allows the jammy blueberry layer to set perfectly. You can use frozen blueberries directly from the freezer with no need to thaw.