Go Back
Lemon blueberry bars stacked three high showing shortbread base, lemon custard filling with burst blueberries, and streusel topping
Luna Hossain

Creamy Lemon Blueberry Bars Recipe

Lemon blueberry bars with a buttery shortbread crust, creamy lemon custard filling, burst blueberry pockets, and sandy streusel topping — no mixer needed, made in one 9×9 inch pan.
Calories: ~210 | Carbs: ~28g | Fat: ~10g | Protein: ~3g | Sugar: ~16g | Sodium: ~65mg
Print Recipe Pin Recipe
Prep Time 20 minutes
Cook Time 47 minutes
Cooling Time 2 hours 30 minutes
Total Time 3 hours 37 minutes
Servings: 16 bars
Course: Bars & Brownies
Cuisine: American
Calories: 210
Ingredients Equipment Method Notes

Ingredients
  

  • For the Shortbread Base and Streusel Topping
  • 2 cups 240g all-purpose flour, spooned and leveled
  • ½ cup 100g plain white granulated cane sugar
  • ¼ tsp 1.5g fine sea salt
  • ¾ cup 170g unsalted butter, cold and cubed into ½-inch pieces
  • For the Lemon Blueberry Filling
  • 3 large eggs room temperature
  • ¾ cup 150g plain white granulated cane sugar
  • ¼ cup 60ml fresh lemon juice (approximately 2 medium lemons)
  • 2 tbsp 12g finely grated lemon zest, zest only, no white pith
  • 3 tbsp 24g all-purpose flour, spooned and leveled
  • ¼ tsp 1.5g fine sea salt
  • 1½ cups 220g fresh whole blueberries, rinsed and fully dried
  • For Finishing
  • Finely grated lemon zest from 1 additional medium lemon added post-bake

Equipment

  • 9x9 inch (23x23cm) light-colored aluminum baking pan
  • Parchment paper cut to fit with 2-inch overhang on two sides
  • Pastry blender or food processor (for cutting cold butter into the flour)
  • Large mixing bowl
  • Medium mixing bowl
  • Whisk
  • Bench scraper or sharp chef's knife (for cutting the finished bars — a thin knife blade will crack the shortbread base)
  • Kitchen scale (strongly recommended over volume measurements)
  • Citrus juicer or reamer
  • Microplane or fine zester
  • Wire cooling rack
  • Oven thermometer

Method
 

  1. Set the oven rack to the middle position and preheat to 350°F (175°C). Line a 9×9 inch (23×23cm) light-colored aluminum baking pan with two strips of parchment paper, each with at least 2 inches of overhang on opposite sides, crossing perpendicular to each other and pressed flat into the corners.
  2. In a large mixing bowl, whisk together 2 cups (240g) all-purpose flour, ½ cup (100g) plain white granulated cane sugar, and ¼ tsp (1.5g) fine sea salt until evenly combined. Add ¾ cup (170g) cold cubed unsalted butter and cut it into the flour mixture using a pastry blender or food processor until the mixture resembles coarse, uneven crumbs with some pea-sized butter pieces still visible — do not overwork.
  3. Measure out approximately ⅔ of the shortbread mixture (roughly 280g) and set aside in the bowl for the streusel topping. Press the remaining ⅓ (roughly 140g) firmly and evenly into the base of the prepared pan to a uniform thickness of approximately ¼ inch (6mm).
  4. Par-bake the base on the middle rack at 350°F (175°C) for 12 to 14 minutes until the edges show the faintest color change and the surface looks dry and matte. Remove from the oven and place on a wire rack. Leave the oven on.
  5. While the base par-bakes, make the filling. In a medium mixing bowl, whisk together ¾ cup (150g) plain white granulated cane sugar and 3 tbsp (24g) all-purpose flour until combined. Add 3 large room-temperature eggs, ¼ cup (60ml) fresh lemon juice, and 2 tbsp (12g) finely grated lemon zest. Whisk vigorously for 60 seconds until smooth, pale, and fully combined with no visible grit.
  6. Pour the lemon filling evenly over the warm par-baked base and spread gently to all four edges with a spatula. Scatter 1½ cups (220g) fresh whole blueberries evenly over the filling and press them gently so they sit into — not on top of — the custard layer. Crumble the reserved ⅔ shortbread mixture evenly over the blueberries, breaking larger clumps into grape-sized pieces. Do not press the streusel down.
  7. Return the assembled pan to the middle rack and bake at 350°F (175°C) for 35 to 40 minutes, until the edges of the base are deep golden brown and the blueberry juices are actively bubbling through the streusel topping in dark purple bursts. If the streusel edges darken before bubbling begins, lay a loose sheet of aluminum foil over the top and continue baking.
  8. Remove the pan from the oven and place on a wire rack. Cool at room temperature for a minimum of 2 hours without cutting. Transfer the pan to the refrigerator for 30 additional minutes. Lift the bars out using the parchment overhang, place on a cutting board, and cut into a 4×4 grid using a bench scraper pressed straight down in one clean motion — wiping the blade between every cut. Scatter finely grated zest from 1 additional lemon over the cut bars immediately.

Notes

Par-bake is mandatory — skipping it produces a soggy base where the filling absorbs into the unbaked dough and the layers never separate.
Use fresh lemon juice only — bottled lemon juice lacks the volatile aromatic compounds that make the filling taste bright and citrusy.
Dry blueberries completely after rinsing — wet berries dilute the filling and prevent the custard from setting cleanly.
Cold butter only for the base — softened or melted butter will not produce the sandy, crumbly shortbread texture this recipe requires.
Frozen blueberries: add straight from frozen without thawing and extend bake time by 5 to 8 minutes.
Use a 9×9 inch light-colored aluminum pan only — dark pans overbrown the base, larger pans produce a custard layer too thin to set properly.
Do not cut before the full 2-hour room temperature cool plus 30-minute refrigerator chill — cutting early causes the base to crumble and the filling to sag.
Scaling: this recipe does not scale to a 9×13 inch pan without significant ratio adjustments — make two separate 9×9 inch pans for a larger batch.
Storage: lidded hard-sided container, parchment between layers, refrigerator up to 4 days, freezer up to 2 months individually wrapped.
Allergens: contains gluten, eggs, dairy.
High altitude (above 3,500ft): check doneness at 30 minutes rather than 35 — the filling may set faster at altitude.