Ingredients
For the Sourdough Croissant Dough
- 100 g active sourdough starter
- 500 g all-purpose flour or bread flour
- 250 g cold milk
- 50 g cold water
- 50 g granulated sugar
- 10 g salt
- 30 g unsalted butter, softened
For the Butter Block
- 250 g unsalted butter
- 1 tablespoon all-purpose flour
For the Blueberry Filling
- 1 cup fresh or frozen blueberries
- 3 tablespoons granulated sugar
- 1 tablespoon cornstarch
- 1 teaspoon fresh lemon juice
- ½ teaspoon vanilla extract
For the Egg Wash
- 1 large egg
- 1 tablespoon milk
Optional Topping
- Powdered sugar
- Lemon glaze
- Fresh blueberries
- Lemon zest
Step 1: Prepare the Sourdough Starter
Before beginning the recipe, make sure your sourdough starter is active and bubbly. An active starter is important because it provides the natural fermentation needed to help the dough rise.
Feed your starter according to your usual routine and allow it to become active before using it. It should look lively and have bubbles throughout.
Using an active starter will help produce lighter and more flavorful croissants.
Step 2: Make the Dough
Add the active sourdough starter, cold milk, cold water, sugar, flour, and salt to a large mixing bowl.
Mix everything together until the ingredients form a rough dough. Make sure there are no large pockets of dry flour remaining.
Let the dough rest for approximately 20–30 minutes.
After resting, add the softened butter. Knead the dough until the butter is completely incorporated and the dough becomes smoother.
You can knead by hand or use a stand mixer. If kneading by hand, work the dough for several minutes until it becomes soft and fairly smooth.
The dough does not need to look completely perfect at this point.
Step 3: First Fermentation
Cover the bowl with plastic wrap, a reusable cover, or a clean kitchen towel.
Allow the dough to ferment at room temperature until it becomes noticeably puffy.
Depending on your room temperature and sourdough starter, this may take approximately 4–6 hours.
The dough does not necessarily need to double completely. You are looking for a noticeable increase in volume and some signs of fermentation.
Once the dough has developed, place it in the refrigerator.
Chilling the dough is very important because cold dough is easier to roll and laminate.
You can refrigerate the dough overnight.
Step 4: Prepare the Butter Block
While the dough is chilling, prepare the butter block.
Place the cold butter between two pieces of parchment paper.
Using a rolling pin, gently pound and roll the butter into a neat rectangle.
Aim for a butter rectangle approximately 20 × 15 cm.
The butter should be cold but flexible. It should not be so hard that it breaks when you roll the dough, and it should not be so soft that it melts.
If the butter becomes too soft, place it back into the refrigerator for a few minutes.
The butter and dough should have similar firmness when you begin laminating.
Step 5: Make the Blueberry Filling
Place the blueberries, sugar, cornstarch, and lemon juice into a small saucepan.
Cook the mixture over medium-low heat while stirring regularly.
As the blueberries heat, they will begin releasing their juices.
Continue cooking for approximately 5–7 minutes, until the mixture thickens into a jam-like consistency.
Remove the saucepan from the heat and stir in the vanilla extract.
Transfer the blueberry filling to a bowl.
Allow it to cool completely.
For the best results, refrigerate the filling until it is cold.
Do not put warm blueberry filling inside the croissant dough because the heat can soften the butter layers.
Step 6: Enclose the Butter
Remove the chilled dough from the refrigerator.
Lightly flour your work surface and roll the dough into a rectangle approximately 30 × 20 cm.
Place the butter block in the center.
Fold the dough over the butter, making sure the butter is completely enclosed.
Press the edges gently to seal the dough.
At this point, you should have a neat package of dough surrounding the butter.
Step 7: First Lamination Fold
Roll the dough into a long rectangle.
Try to roll evenly so that the butter remains distributed throughout the dough.
Once the dough is long enough, fold it into thirds like you would fold a letter.
This is your first fold.
Wrap the dough and place it in the refrigerator for approximately 30–45 minutes.
Chilling between folds is important because it keeps the butter firm.
Step 8: Second Lamination Fold
Remove the chilled dough from the refrigerator.
Roll it into another long rectangle.
Again, fold the dough into thirds.
Wrap it and refrigerate it for another 30–45 minutes.
If the dough feels soft, sticky, or difficult to roll, return it to the refrigerator.
Never try to force the dough when the butter is becoming warm.
Step 9: Roll the Dough for Cutting
After the second fold, chill the dough until it is firm but still flexible.
Roll the dough into a large rectangle approximately 4–5 mm thick.
Try to keep the thickness as even as possible.
If the edges are uneven, you can carefully trim them with a sharp knife or pizza cutter.
Clean edges can help create more consistent croissants.
Step 10: Cut the Croissant Shapes
Using a sharp knife or pizza cutter, cut the dough into long triangles.
Each triangle should have a wide base and a pointed tip.
Make a small slit in the middle of the wide end of each triangle.
This small cut helps the croissant spread into its classic shape.
Avoid making the triangles too small because you need enough space to roll them properly.
Step 11: Add the Blueberry Filling
Place a small amount of chilled blueberry filling near the wide end of each triangle.
Be careful not to use too much filling.
It can be tempting to add a generous spoonful, but excessive filling may leak out during baking and interfere with the pastry layers.
A thin, concentrated strip of blueberry filling is enough to give each croissant plenty of fruity flavor.
Step 12: Shape the Croissants
Gently stretch each triangle lengthwise.
Starting at the wide end, carefully roll the dough toward the pointed tip.
Keep the roll fairly loose rather than squeezing it tightly.
The pointed end should finish underneath the croissant so it does not unravel during baking.
Place each shaped croissant on a parchment-lined baking tray.
Leave plenty of space between the croissants because they will expand during proofing and baking.
Step 13: Final Proof
Cover the croissants loosely and allow them to proof at room temperature.
The final proof may take approximately 3–5 hours, depending on your kitchen temperature and the strength of your sourdough starter.
Do not rely only on the clock.
Instead, look at the croissants.
They should become visibly larger, lighter, and puffy.
When the tray is gently moved, properly proofed croissants should have a slight jiggle.
If they still look dense and firm, give them more time.
Step 14: Prepare the Egg Wash
Whisk one egg with one tablespoon of milk.
Once the croissants have finished proofing, gently brush the egg wash over their surfaces.
Use a light hand.
Avoid pressing the pastry because you do not want to deflate the delicate layers.
Also avoid allowing large amounts of egg wash to collect underneath the croissants.
Step 15: Bake the Croissants
Preheat your oven to 200°C (400°F).
Place the croissants into the oven.
Immediately reduce the oven temperature to approximately 190°C (375°F).
Bake for about 20–25 minutes, or until the croissants are deeply golden brown and beautifully puffed.
The exact baking time can vary depending on the size of your croissants and your oven.
Keep an eye on them during the final few minutes.
The outside should look crisp and golden rather than pale.
Step 16: Cool Before Serving
Remove the croissants from the oven and let them sit on the baking tray for about 5 minutes.
Then carefully transfer them to a wire rack.
Allow them to cool before eating.
The blueberry filling will be extremely hot immediately after baking, so cooling also makes them safer and easier to enjoy.
Optional Lemon Glaze
A simple lemon glaze pairs beautifully with blueberry croissants.
Mix powdered sugar with a small amount of fresh lemon juice until you have a smooth glaze.
Drizzle it over completely cooled croissants.
You can also add a little lemon zest for extra citrus flavor.
The bright lemon flavor complements the sweet blueberry filling and buttery pastry.
Helpful Tips for Successful Croissants
Keep the Butter Cold
Cold butter is one of the most important parts of successful croissant making.
If the butter becomes too warm, it can melt into the dough and destroy the layers.
If you notice the dough becoming soft or greasy, put it back in the refrigerator.
Don’t Rush the Fermentation
Sourdough croissants need time.
The fermentation and proofing process can take several hours, and the exact timing depends on temperature and starter activity.
Watch the dough rather than following the clock alone.
Use Thick Blueberry Filling
The filling should be thick enough to stay inside the pastry.
A watery filling can escape through the dough during baking.
Cornstarch helps thicken the blueberry mixture and makes it easier to use as a pastry filling.
Don’t Overfill
More filling does not necessarily mean better croissants.
Too much blueberry mixture can cause leaks and make shaping difficult.
Use a moderate amount for each croissant.
Chill Between Folds
If the dough becomes difficult to handle, stop and chill it.
Trying to roll warm croissant dough can cause the butter to spread and merge with the dough.
Give the Croissants Enough Space
Place the shaped croissants several centimeters apart on the baking tray.
They will expand considerably during final proofing and baking.
How to Store Blueberry Croissants
Freshly baked croissants are best enjoyed on the same day.
If you have leftovers, store them in an airtight container at room temperature for approximately 1–2 days.
For a crisp texture, reheat them in a preheated oven at about 160°C (320°F) for 5–8 minutes.
Avoid microwaving them if you want to maintain their flaky texture because microwaving can make the pastry soft.
Can You Freeze Them?
Yes. Sourdough blueberry croissants can be prepared ahead of time.
After shaping the croissants, place them on a parchment-lined tray and freeze them until firm.
Transfer them to a freezer-safe container or bag.
When you are ready to bake, allow them to thaw and complete their final proof at room temperature before applying the egg wash and baking.
This is a convenient option when you want freshly baked croissants without doing all the preparation on the same morning.
Serving Ideas
These blueberry croissants are wonderful for breakfast or brunch.
Serve them with fresh blueberries, strawberries, raspberries, or other seasonal fruit.
For a richer dessert-style presentation, drizzle cooled croissants with lemon glaze and add a light dusting of powdered sugar.
You can also serve them with yogurt, whipped cream, or a cup of coffee or tea.
The buttery pastry and sweet-tart blueberry filling make these croissants special enough for holidays and celebrations while still being delicious for an ordinary weekend breakfast.
Final Thoughts
Homemade Sourdough Blueberry Croissants are a rewarding baking project for anyone who enjoys sourdough and classic pastries. They require patience, especially during fermentation, lamination, and final proofing, but each step contributes to the final flaky texture.
The combination of naturally fermented sourdough dough, rich butter, and homemade blueberry filling creates a pastry that is crisp on the outside, airy inside, and bursting with fruity flavor.
Once you become comfortable with the basic process, you can experiment with other fillings such as raspberry, strawberry, cherry, lemon curd, chocolate, or cream cheese.
For the best results, remember the most important rules: keep the butter cold, keep the filling thick and chilled, don’t rush the fermentation, and allow the shaped croissants enough time to proof.
With a little patience, you can enjoy bakery-style sourdough blueberry croissants fresh from your own oven.
