This recipe combines classic croissant lamination with sourdough flavor and a sweet blueberry filling. It takes about 2 days because of the fermentation and chilling time, but the texture is flaky, buttery, and worth it.

Yield

10–12 croissants

Ingredients

Sourdough Croissant Dough

• 500 g bread flour
• 60 g sugar
• 10 g salt
• 100 g active sourdough starter (100% hydration)
• 250 g cold milk
• 50 g cold water
• 40 g softened butter

Butter Block

• 250 g unsalted butter (high-fat European style preferred)

Blueberry Filling

• 250 g blueberries (fresh or frozen)
• 50 g sugar
• 1 tbsp lemon juice
• 1 tbsp cornstarch
• 2 tbsp water
• 1 tsp vanilla extract

Egg Wash

• 1 egg
• 1 tbsp milk

Day 1 — Make the Dough

1. In a large bowl, mix:
   • flour
   • sugar
   • salt
2. Add:
   • sourdough starter
   • milk
   • water
   • softened butter
3. Mix until a rough dough forms.
4. Knead for 6–8 minutes until smooth.
5. Cover and rest 30 minutes.
6. Perform 2–3 stretch-and-folds every 30 minutes.
7. Cover and refrigerate overnight (8–12 hours).

Prepare the Butter Block

1. Place butter between parchment paper.
2. Roll into a rectangle about:
   • 7 x 10 inches
   • around 1 cm thick
3. Chill until firm but still flexible.

Day 2 — Laminate the Dough

Lock In the Butter

1. Roll dough into a rectangle twice the size of the butter block.
2. Place butter in the center.
3. Fold dough over butter like a book.
4. Seal edges.

First Fold

1. Roll into a long rectangle.
2. Fold into thirds like a letter.
3. Chill 30–45 minutes.

Second Fold

Repeat rolling and folding.

Chill again 30–45 minutes.

Third Fold

Repeat one final fold.

Chill at least 1 hour before shaping.

Make the Blueberry Filling

1. Combine blueberries, sugar, lemon juice, vanilla, and water in a saucepan.
2. Cook over medium heat until berries burst.
3. Mix cornstarch with 1 tbsp water and stir in.
4. Cook until thick.
5. Cool completely before using.

Shape the Croissants

1. Roll dough into a large rectangle about ¼ inch thick.
2. Cut triangles:
   • base about 4 inches wide
   • height about 8–9 inches
3. Add 1 tbsp blueberry filling near the base.
4. Gently roll toward the tip.
5. Curve ends slightly into crescent shapes.

Final Proof

1. Place shaped croissants on parchment-lined trays.
2. Cover lightly.
3. Proof at cool room temperature for 4–7 hours.

They should look puffy and slightly jiggly.

Bake

1. Preheat oven to 200°C (390°F).
2. Brush with egg wash.
3. Bake:
   • 10 minutes at 200°C
   • then reduce to 180°C (350°F)
   • bake another 12–15 minutes

Bake until deeply golden.

Optional Blueberry Glaze

Mix:

• ½ cup powdered sugar
• 1–2 tsp blueberry juice or milk

Drizzle over cooled croissants.

Tips for Best Results

• Keep dough cold during lamination.
• If butter softens too much, chill immediately.
• Use strong bread flour for better layers.
• Under-proofed croissants will leak butter.
• Fully proofed croissants wobble slightly when tray is shaken.

Storage

• Best eaten same day.
• Reheat at 170°C for 5 minutes.
• Freeze baked croissants up to 1 month.

Enjoy your flaky homemade sourdough blueberry croissants!