Blueberry Lemon Bars
These blueberry lemon bars are the perfect mix of bright citrus flavor and sweet berries in every bite. They come together quickly with a buttery oat crust layered with a fresh lemon blueberry filling, then finished with a crumbly oat topping for the ultimate fruity dessert. With only about 15 minutes of prep time, they’re easy to make ahead, freezer-friendly, and versatile enough to enjoy as a grab-and-go breakfast or a delicious dessert.
Ingredients
Oat Crust & Crumble Topping
- 2 quick oats Rolled oats work but quick oats hold better
- 1 cup all-purpose flour Or 1:1 gluten-free baking flour
- ½ cup light brown sugar Packed
- ¼ tsp baking powder
- ¼ tsp sea salt
- ½ cup unsalted butter Melted and slightly cooled
- 1 vanilla extract
- 1 tsp lemon zest From about 1 lemon
Blueberry Lemon Filling
- 2 cups blueberries Fresh or frozen (no need to thaw)
- 2 tbsp fresh lemon juice From about 1 large lemon
- 1 tsp lemon zest
- 1 ½ tbsp cornstarch Arrowroot powder works as a substitute
Instructions
- Step 1 — Preheat & Prep the Filling Preheat your oven to 350°F (175°C). In a medium bowl, combine the blueberries, granulated sugar, fresh lemon juice, lemon zest, and cornstarch. Stir gently until the berries are evenly coated. Set aside.Step 2 — Mix the Dry Oat Base In a large bowl, whisk together the quick oats, flour, light brown sugar, baking powder, and sea salt until well combined.Step 3 — Add the Wet Ingredients Pour in the melted butter, then add the vanilla extract and lemon zest. Stir until everything is fully incorporated. The mixture will look crumbly — that is exactly right.Step 4 — Press the Base Layer Line an 8×8 inch baking pan with parchment paper, leaving overhang on two sides for easy removal. Press approximately two-thirds of the oat mixture firmly and evenly into the bottom of the pan to form the crust.Step 5 — Add the Blueberry Filling Spoon the blueberry lemon mixture evenly over the pressed oat crust, spreading it all the way to the edges in an even layer.Step 6 — Add the Crumble Topping Scatter the remaining oat mixture loosely over the top of the blueberry filling. Do not press it down — keep it crumbly for the best topping texture.Step 7 — Bake Place the pan in the preheated oven and bake for 30 to 35 minutes, until the berry filling is bubbling around the edges and the oat topping is golden brown.Step 8 — Cool & Slice Remove from the oven and allow the bars to cool completely in the pan. For clean, handheld bars, refrigerate for at least 2 hours before slicing. Run a knife under hot water, slice, then wipe the blade clean between each cut. For a warm, fork-served version, skip the refrigeration and dig in once cooled slightly.
Notes
- Adjust sweetness to your berries. Taste them first — peak-season berries may need less sugar, while tart or off-season berries may need a little more.
- For the cleanest slices, refrigerate for 2–3 hours before cutting. Run your knife under hot water and wipe between cuts.
- To freeze, cool completely, slice into bars, wrap individually, and freeze in an airtight container for up to 3 months.
- To make dairy-free/vegan, swap butter for a plant-based stick butter. No eggs in this recipe, so that's the only change needed.
- To make gluten-free, use a certified 1:1 gluten-free flour and certified gluten-free oats.
- Storage: Keep refrigerated in an airtight container for up to one week. Let sit at room temperature for 15 minutes before serving, or warm briefly in the microwave.