This is blueberry pie without the hassle of making a homemade pie crust! To prepare these easy blueberry pie bars, layer a buttery brown sugar crust, jammy blueberry filling, and a crumbly oat topping. The crust and crumble topping are made from the same mixture, so there’s no need to dirty an additional bowl. Cool completely before cutting.
Crust + Topping
- 1 and 1/2 cups (188g) all-purpose flour (spooned & leveled)
- 1 cup (85g) + 2 Tablespoons old-fashioned whole rolled oats, divided
- 1/2 cup (100g) packed light or dark brown sugar
- 1 teaspoon baking powder
- 1 teaspoon lemon zest
- 1/4 teaspoon ground cinnamon
- 1/8 teaspoon salt
- 10 Tablespoons (142g) unsalted butter, melted
- 4 and 1/2 cups (about 640g) blueberries, fresh is best*
- 1/2 cup (100g) granulated sugar
- 2 Tablespoons (15g) cornstarch
- 1 Tablespoon lemon juice
- 2 teaspoons lemon zest
- Preheat oven to 350°F (177°C). Line a 9-inch square baking pan (I love this one and this one) with parchment paper, leaving an overhang on the sides to easily lift the bars out of the pan. Set aside.
- Make the crust: Whisk the flour, 1 cup (85g) oats, brown sugar, baking powder, lemon zest, cinnamon, and salt together in a medium bowl. Add the melted butter and stir until the mixture resembles moist crumbly sand and no dry spots remain. You will have a little more than 3 cups of crust mixture, or about 520g. Press 2/3 of the mixture (about 2 cups/345g—doesn’t have to be exact) into the prepared baking pan. Press it into the pan with your hands, a large spoon or spatula, or the bottom of a measuring cup to form a crust. Bake for 10 minutes, and then remove from the oven to slightly cool.
- Make the filling: Place the blueberries, sugar, cornstarch, and lemon juice in a saucepan over medium heat on the stove and stir gently to combine. Cook and stir for 2–3 minutes until the cornstarch and sugar begin to dissolve and the berries look evenly wet. Remove from heat and stir in the lemon zest.
- Pour/spread the filling over the warm crust. Stir 2 Tablespoons oats into the remaining crumble mixture, then sprinkle it all over the filling, and lightly press it down with the back of a large spoon or flat spatula.
- Bake for about 45–55 minutes, or until the top is lightly browned and the blueberry filling is bubbling around the edges.
- Remove from the oven and allow the bars to cool completely in the pan set on a wire rack. Feel free to cover and refrigerate the cooled bars for up to 1 day before cutting into squares.
- Lift the cooled bars out of the pan using the overhang on the sides and cut into squares.
- Cover and store leftover blueberry pie bars at room temperature for up to 2 days or in the refrigerator for up to 1 week.
- Make Ahead & Freezing Instructions: You can refrigerate the cooled bars before cutting into squares, see step 6. Baked and cooled bars freeze well up to 3 months. Thaw overnight in the refrigerator and bring to room temperature, if desired, before serving.
- Special Tools (affiliate links): 9-Inch Square Baking Pan or this 9-Inch Square Baking Pan | Glass Mixing Bowl | Citrus Zester | Citrus Juicer
- Can I Bake This in a 9×13-inch Pan? You can, but I have had better results baking a smaller batch, as written, in the 9-inch pan. If you want to make a larger batch, double each ingredient (only use 8 cups of blueberries) and bake in a 9×13-inch pan. Increase crust pre-bake time to 18 minutes. Increase the bake time after adding the filling & crumble topping to 1 hour, or until filling is bubbling.
- Fresh Blueberries: It’s best to use fresh blueberries in this recipe. If you’d like to use frozen, follow the recipe as written and sub in frozen blueberries (do not thaw). Keep in mind that the filling will be much juicier.
- Update in 2023: This recipe used to call for 3 cups (about 525g) of blueberries in the filling, and 1 peeled and sliced apple. To make the blueberry apple version, follow the recipe instructions above through step 3. After spreading blueberry filling onto the warm crust in step 4, top evenly with sliced apple, and then sprinkle remaining crumble mixture on top. Continue with the recipe as written.
- Looking for a vegan and gluten-free version? Try my healthy berry streusel bars.
Keywords: blueberry pie bars