Sourdough Blueberry Croissants

Sourdough blueberry croissants are a fun twist on the classic French croissant. They have crisp, flaky layers on the outside, a soft and buttery center, and a sweet blueberry filling tucked inside. The sourdough starter adds a light tang that balances the sweetness and gives the croissants a deeper flavor.

These croissants take some time because the dough needs to ferment, chill, and be folded several times. But the result is worth it. Once baked, the butter creates thin layers that puff up beautifully, while the blueberry filling becomes warm, sweet, and jammy.

Ingredients

For the Sourdough Croissant Dough

• 100g active sourdough starter
• 500g bread flour
• 250g cold whole milk
• 50g granulated sugar
• 10g salt
• 30g unsalted butter, softened
• 1 large egg

For the Butter Layer

• 250g unsalted butter, cold

For the Blueberry Filling

• 1 cup fresh or frozen blueberries
• 3 tablespoons granulated sugar
• 1 tablespoon lemon juice
• 1 tablespoon cornstarch
• 1 tablespoon water
• 1/2 teaspoon vanilla extract

For the Egg Wash

• 1 large egg
• 1 tablespoon milk

Step 1: Make the Sourdough Dough

Start by making the dough the day before you plan to bake the croissants.

In a large bowl, combine the active sourdough starter, milk, sugar, egg, and softened butter. Mix until the ingredients are well combined.

Add the bread flour and salt. Stir until a rough dough forms. The dough may look slightly sticky at first, but that is normal.

Transfer the dough to a lightly floured work surface. Knead it gently for about 5 to 8 minutes. You do not need to develop the dough as much as you would for regular bread. The goal is to create a smooth and fairly firm dough.

Shape the dough into a ball and place it in a lightly greased bowl. Cover it with plastic wrap or a lid.

Let the dough rest at room temperature for about 2 to 4 hours, depending on the temperature of your kitchen. It does not need to double in size at this stage.

After the initial rest, place the dough in the refrigerator overnight. The cold temperature will slow the fermentation and make the dough much easier to roll.

Step 2: Prepare the Blueberry Filling

While the dough is chilling, make the blueberry filling.

Add the blueberries, sugar, and lemon juice to a small saucepan. Cook over medium heat for several minutes, stirring often.

As the blueberries heat up, they will begin to release their juice. Lightly crush some of the berries with the back of a spoon, but leave a few whole pieces for texture.

Mix the cornstarch with water in a small bowl to create a smooth slurry. Add it to the blueberry mixture and stir well.

Continue cooking for 1 to 2 minutes, until the mixture becomes thick and jam-like.

Remove the pan from the heat and stir in the vanilla extract.

Allow the filling to cool completely. It is important that the filling is cold before it is added to the croissants. Warm filling can make the butter melt and cause problems with the layers.

Step 3: Make the Butter Block

Place the cold butter between two sheets of parchment paper.

Using a rolling pin, gently pound and roll the butter into a rectangle about 20 x 25 cm.

Try to keep the butter evenly thick from one end to the other. If the butter becomes too soft, place it in the refrigerator for a few minutes.

The butter should be cold but flexible. It should bend without breaking when you start laminating the dough.

Step 4: Laminate the Dough

Remove the chilled dough from the refrigerator.

Roll it into a rectangle that is slightly larger than the butter block. Place the butter in the center of the dough and fold the dough over it, completely covering the butter.

Press the edges together to seal the butter inside.

Now roll the dough into a long rectangle. Try to roll gently and evenly. If the butter starts to soften or squeeze out, stop and chill the dough.

Fold the dough into thirds, similar to folding a letter.

This is your first fold.

Wrap the dough and refrigerate it for about 30 to 45 minutes.

Repeat the rolling and folding process two more times, chilling the dough between each fold.

Keeping the dough cold is one of the most important parts of making good croissants. If the butter becomes too soft, it can blend into the dough instead of creating separate flaky layers.

Step 5: Shape the Croissants

After the final fold, refrigerate the dough for at least 1 hour.

Roll the dough into a large rectangle about 4 to 5 mm thick.

Trim the edges if needed so the rectangle is neat and even.

Cut the dough into long triangles. Each triangle should be wide at the base and come to a sharp point.

Place a small spoonful of the cooled blueberry filling near the wide end of each triangle. Do not add too much filling because it can leak during baking.

Starting at the wide end, gently roll each triangle toward the pointed end.

Place the shaped croissants on a parchment-lined baking sheet with the point tucked underneath.

Curve the ends slightly toward the center if you want the traditional croissant shape.

Step 6: Proof the Croissants

Cover the croissants loosely and allow them to proof at room temperature.

Because this is sourdough dough, the proofing time can vary. It may take around 3 to 6 hours depending on the temperature of your kitchen and the strength of your starter.

Do not rush this step.

The croissants should look noticeably puffy and lighter. If you gently shake the baking sheet, they should have a slight wobble.

Avoid placing them somewhere extremely warm. High heat can cause the butter to melt before the croissants reach the oven.

Step 7: Add the Egg Wash

When the croissants are fully proofed, preheat your oven to 400°F (200°C).

Whisk together the egg and milk.

Gently brush the egg wash over the tops of the croissants. Try not to press down on the dough while brushing.

Avoid getting too much egg wash on the cut edges because it can sometimes seal the layers.

Step 8: Bake

Place the croissants in the preheated oven.

Bake at 400°F (200°C) for about 10 minutes. Then reduce the temperature to 375°F (190°C) and continue baking for another 12 to 18 minutes.

The exact baking time will depend on the size of your croissants and your oven.

The finished croissants should be deeply golden brown, crisp on the outside, and nicely puffed.

If blueberry filling has leaked out during baking, do not worry. A little filling around the edges can become caramelized and delicious.

Allow the croissants to cool on a wire rack for at least 15 to 20 minutes before serving.

Tips for Perfect Sourdough Blueberry Croissants

Keep the butter cold. Cold butter is the key to creating distinct layers. If the butter starts melting, chill the dough before continuing.

Use an active starter. Your sourdough starter should be bubbly and active before you begin. A weak starter can lead to slow fermentation and dense croissants.

Do not overfill. Blueberry filling is delicious, but too much can cause the croissants to burst or become difficult to roll.

Watch the proofing stage. Under-proofed croissants can be heavy and dense. Properly proofed croissants should look puffy and airy.

Give the dough time. Sourdough croissants are not a quick recipe. The long fermentation adds flavor and helps create a tender texture.

Chill whenever necessary. If the dough becomes difficult to handle or the butter starts getting soft, put everything back in the refrigerator.

How to Store Blueberry Croissants

Freshly baked sourdough blueberry croissants are best served the same day. If you have leftovers, store them in an airtight container at room temperature for up to 2 days.

To bring back some of their crisp texture, reheat them in a 325°F (165°C) oven for about 5 to 8 minutes.

You can also freeze shaped, unbaked croissants. Place them on a tray and freeze until solid, then transfer them to a freezer-safe bag. When ready to bake, thaw and proof them before applying the egg wash and baking.

Serving Ideas

These croissants are wonderful with a cup of coffee or tea. They can be served for breakfast, brunch, or as a sweet afternoon snack.

For an extra special finish, dust the cooled croissants with powdered sugar. You can also drizzle them with a simple lemon glaze made from powdered sugar and fresh lemon juice.

A little cream cheese glaze works well too. The tangy cream cheese pairs nicely with the sweet blueberry filling and sourdough flavor.

Final Thoughts

Sourdough blueberry croissants combine the best parts of homemade sourdough baking and classic pastry. The outside becomes crisp and golden, while the inside stays soft and buttery. The blueberry filling adds a bright fruit flavor that makes every bite feel special.

They do require patience, but the process is simple once you understand the basic steps. Keep the dough cold, use an active starter, avoid overfilling, and give the croissants enough time to proof.

With a little practice, these homemade sourdough blueberry croissants can become a favorite weekend breakfast.