When you want a rustic, bakery-worthy dessert that uses up sourdough discard while showcasing fresh summer fruit, this Lemon Blueberry Sourdough Galette is an absolute showstopper. A buttery, flaky pastry crust enriched with the subtle tang of sourdough starter enfolds a juicy, sweet blueberry filling spiked with fresh lemon zest and juice.
The secret to a crisp galette crust that never turns soggy under juicy fruit is Cornstarch Binding and Chilling the Assembly Before Baking. Tossing blueberries with cornstarch and sugar thickens their natural juices into a glossy jam as they bake, while chilling the folded galette in the fridge for 15 minutes before it hits a hot oven solidifies the butter for maximum flaky layers.
Why You’ll Love This Galette
- Rustic & Forgiving: No pie dish or crimping required—simply roll the dough, pile the fruit in the middle, and fold the edges over.
- Great Use for Sourdough Discard: Adds a subtle depth of flavor and tender texture to the pie dough without needing a long fermentation.
- Bright & Sweet Balance: Zesty lemon cuts through the sweet, jammy blueberries for a refreshing finish.
- Ultra-Flaky Pastry: Cold butter pockets create crisp, shatteringly tender crust layers.
Key Ingredients Overview
- Sourdough Discard: Unfed starter straight from the fridge adds moisture and a delicious sourdough tang to the pastry.
- Cold Unsalted Butter: Cut into the flour to create flaky, buttery dough layers.
- Fresh or Frozen Blueberries: Forms a rich, jammy center that bursts during baking.
- Lemon Zest & Juice: Brightens the berry filling with fresh citrus flavor.
- Cornstarch or Tapioca Starch: Thickens the fruit juices so the crust stays crisp on the bottom.
Step-by-Step Instructions
1.The Sourdough Pastry Dough:10 min.
In a large bowl, combine 1¼ cups all-purpose flour, 1 tablespoon sugar, and ½ teaspoon salt. Cut in ½ cup (1 stick) cold, cubed unsalted butter using a pastry cutter until pea-sized crumbs form. Stir in ½ cup cold sourdough discard and 1 to 2 tablespoons ice water just until the dough comes together. Shape into a disc, wrap in plastic, and chill in the fridge for 30 minutes.
2.The Lemon Blueberry Filling:5 min.
In a medium bowl, gently toss 3 cups of fresh blueberries with 3 tablespoons granulated sugar, 1½ tablespoons cornstarch, 1 teaspoon fresh lemon zest, 1 tablespoon fresh lemon juice, and ½ teaspoon vanilla extract until the berries are evenly coated.
3.The Roll & Rustic Fold:5 min.
Preheat your oven to $200^\circ\text{C}$ ($400^\circ\text{F}$) and line a baking sheet with parchment paper. On a lightly floured surface, roll the chilled sourdough dough into a 12-inch circle. Transfer to the baking sheet. Mound the blueberry filling into the center, leaving a 2-inch border around the edges. Fold the edges of the dough over the fruit, pleating as you go.
4.The Golden Bake:35 min.
Brush the folded crust edges with 1 beaten egg (or milk) and sprinkle generously with coarse turbinado sugar for crunch. Chill the assembled galette in the freezer for 10 minutes (or fridge for 15 minutes). Bake for 35 to 40 minutes until the crust is deep golden brown and the berry juices are thick and bubbling.
5.The Cool & Serve:10 min.
Let the galette cool on the baking sheet for at least 15 to 20 minutes so the fruit filling sets. Slice and serve warm with a scoop of vanilla bean ice cream or whipped cream!
Expert Tips for Success
- Keep Ingredients Cold: Cold butter and cold sourdough discard are key to a flaky galette. If the dough warms up while rolling, chill it in the fridge before putting it in the oven.
- Don’t Skip the Starch: Blueberries release a tremendous amount of liquid as they burst. Cornstarch binds those juices into a thick glaze so they don’t run over the baking sheet or make the bottom crust soggy.
- Egg Wash + Coarse Sugar: Brushing the crust with egg wash and sprinkling turbinado or coarse sugar gives it a shiny, crunchy, bakery-style crust finish.
The Recipe Card
- Prep Time: 20 mins
- Chilling Time: 45 mins
- Bake Time: 35 mins
- Total Time: 1 hour 40 mins
- Yield: 6 to 8 Servings
Ingredients:
- The Sourdough Pastry: 1¼ cups All-Purpose Flour, 1 tbsp Granulated Sugar, ½ tsp Salt, ½ cup (1 stick) Unsalted Butter (cold & cubed), ½ cup Cold Sourdough Discard, 1–2 tbsp Ice Water.
- The Lemon Blueberry Filling: 3 cups Blueberries (fresh or frozen), 3 tbsp Granulated Sugar, 1½ tbsp Cornstarch, 1 tsp Fresh Lemon Zest, 1 tbsp Fresh Lemon Juice, ½ tsp Vanilla Extract.
- The Finish: 1 Egg (beaten with 1 tsp water), 1 tbsp Coarse Turbinado Sugar.
Instructions:
Cut cold butter into flour, sugar, and salt. Stir in cold sourdough discard and ice water to form a dough disc; chill for 30 minutes. Toss blueberries with sugar, cornstarch, lemon zest, lemon juice, and vanilla. Roll dough into a 12-inch circle, pile berries in the middle, and fold pastry edges over the fruit. Brush edges with egg wash, sprinkle with coarse sugar, and bake at $200^\circ\text{C}$ ($400^\circ\text{F}$) for 35–40 minutes until golden and bubbling. Cool before slicing.
