Sourdough Croissants

Ingredients

The Levain

Build this the day before so it's ripe when you mix the dough. It replaces the commercial yeast entirely.

• 20g (1 tbsp) ripe sourdough starter
• 60g (½ cup) bread flour
• 60g (¼ cup) water, room temperature

Détrempe (The Dough)

The enriched dough that will encase the butter. Mixed cool so the levain works slowly. The 40g of butter here is separate from the lamination block.

• 450g (3⅔ cups) bread flour (11.5–12.5% protein)
• 100g (½ cup) ripe levain (from above)
• 210g (⅞ cup) cold whole milk
• 20g (1 tbsp + 1 tsp) cold water
• 55g (¼ cup + 1 tbsp) granulated sugar
• 10g (1¾ tsp) fine sea salt
• 40g (3 tbsp) unsalted butter, softened

Beurrage (Butter Block)

The butter that builds your layers. High fat, European style. Same block as the classic French version.

• 250g (1 cup + 2 tbsp) European unsalted butter (82–84% fat), cold

Egg Wash

One wash, brushed on right before baking for color and shine.

• 50g (1 large) large egg
• 15g (1 tbsp) whole milk

Total flour: 500g

Hydration: 56%

Pro tip: Plan the calendar first. For the Saturday bake-along, here's your clock: build your levain Thursday morning, mix the dough Thursday night, laminate Friday, shape and bake Saturday. Your starter has to be strong for these, since there's no commercial yeast backing it up. Feed it for a day or two beforehand until it reliably doubles or triples within 4 to 6 hours of a feeding. A sluggish starter gives you dense, tight croissants no amount of extra proofing fully fixes. And buy the best European butter you can afford. Higher fat means cleaner layers and less leakage.

Equipment

• Digital Kitchen Scale
• Stand Mixer with Dough Hook
• Long Rolling Pin
• Ruler or Measuring Tape
• Bench Scraper
• Pizza Cutter or Sharp Knife
• Pastry Brush
• Two Parchment-Lined Sheet Pans
• Plastic Wrap

Method

Build the Levain

This is your engine, the same levain you build for any sourdough bake, just feeding croissant dough this time. Build it 8 to 12 hours before you mix the dough.

1. Mix the levain. Combine the ripe starter, bread flour, and room-temperature water in a jar. Stir smooth, cover loosely, and leave at warm room temperature, around 75 to 78F (24 to 26C).
2. Wait for ripe and bubbly. Let it ferment 8 to 12 hours until doubled, domed, and bubbly, with a pleasant tang. A float test confirms it: a small spoonful should float in water. You need 100g for the dough. The little bit left over feeds your jar.

Wait: PT10H

Tip: For a Saturday bake, build the levain Thursday morning and mix the dough Thursday night, so the levain peaks right when you need it.

Make the Détrempe

The base dough. We mix it cool and barely develop it. The folding does the real gluten work later. Sourdough takes longer to come together than a yeasted dough, so give it time.

1. Combine the ingredients. In a stand mixer with the dough hook, combine the bread flour, sugar, salt, ripe levain, cold milk, cold water, and softened butter. Mix on low 3 minutes to combine, then medium-low 5 to 7 minutes until smooth and pulling cleanly from the bowl. It should feel soft and pliable, not stiff. Don't overmix. Overdeveloped dough fights you during lamination.
2. Shape into a rectangle. Turn the dough out and pat it into a flat rectangle roughly 8 x 6 inches. Wrap tightly in plastic.
3. Overnight cold rest. Refrigerate 10 to 16 hours. By morning the dough should look slightly puffed and relaxed, not ballooned. If your starter is strong, lean toward the shorter end. This is a sourdough, so unlike a yeasted dough it keeps fermenting slowly in the cold, and a dough that goes too far turns slack and loses its layers.

Wait: PT12H

Tip: Keep this dough cooler than a normal sourdough loaf. You're protecting the butter you'll add tomorrow, and a cold, relaxed dough is a forgiving dough. Strong starter? Set an alarm for the 10-hour mark and check it.

Build the Butter Block (Beurrage)

Turn the cold butter into a flat, even slab the same firmness as your dough. This is the heart of the croissant.

1. Pound the butter. Slice the cold butter into pieces and arrange them into a square on parchment. Cover with a second sheet. Pound firmly with the rolling pin, then roll into a 7 x 7 inch square about ½ inch thick.
2. Trim and chill. Trim the edges clean, set the trimmings back in the center, and roll smooth. Wrap and refrigerate at least 30 minutes. Target temp is 55 to 60F (13 to 16C): it should bend without cracking.

Wait: PT30M

Tip: This is the babka butter rule again. Cold butter holds its layers, warm butter melts in and vanishes. Get the butter and dough to the same cool, bendable feel and lamination gets easy.

Lock In the Butter

The dough and butter become one laminated package. Both should feel similar in firmness. Neat corners here pay off in every layer later.

1. Roll out the dough. Roll the chilled détrempe into a 10 x 10 inch square with even thickness and square corners.
2. Position the butter. Place the butter block diagonally in the center so it sits like a diamond inside the square.
3. Fold over the butter. Fold the dough corners inward to completely enclose the butter. Pinch all seams firmly. No butter should show. If it peeks through, dust lightly with flour and chill before continuing.

Tip: If the dough warms up or fights you, stop and chill it 15 to 20 minutes. Sourdough dough is a little more extensible than yeasted, but the butter still hates heat.

First Letter Fold

This is where the layers begin. Three letter folds produce 27 alternating butter layers, the same stack, fold, roll motion from the zebra bake.

1. Roll into a rectangle. Roll the package to roughly 8 x 24 inches, 4 to 5mm thick. Roll firmly but evenly, lengthwise. Brush off excess flour.
2. Execute the fold. Fold the bottom third up, then the top third down over it, like a business letter. That's your first fold.
3. Chill. Wrap tightly and refrigerate 60 minutes.

Wait: PT1H

Tip: If butter ever cracks through, dust the spot with flour and keep going. A little breakthrough is normal.

Second Letter Fold

Rotate the dough 90 degrees so the folded edges sit left and right like a book, then roll and fold again.

1. Roll and fold again. Rotate 90 degrees. Roll again to 8 x 24 inches, 4 to 5mm thick, and execute another letter fold.
2. Chill. Wrap tightly and refrigerate 60 minutes.

Wait: PT1H

Tip: Always rotate a quarter turn before each roll, so the open edge is on your right. That keeps you rolling across the layers, never sealing them shut.

Third Letter Fold, Then Overnight Rest

One final fold brings you to 27 layers, then a cold rest relaxes the gluten, firms the butter, and deepens the sourdough flavor.

1. Roll, fold, wrap. Rotate 90 degrees, roll to 8 x 24 inches, and execute the third letter fold. You now have 27 butter layers.
2. Overnight rest. Wrap tightly and refrigerate 10 to 16 hours. The dough should relax and puff slightly, not balloon. Strong starter, lean to the shorter end. This final rest relaxes the gluten, firms the butter, builds flavor, and makes shaping easier.

Wait: PT12H

Tip: Longer within that 10-to-16-hour window means more tang. Shorter keeps it milder. Past 16 hours you risk a slack dough that won't hold its layers.

Roll, Cut, and Shape

The dough should feel cold and firm. Work quickly so the butter stays cool. Measure rather than eyeball, because lamination mistakes show up loud once baked.

1. Roll final thickness. Roll into a long rectangle, about 8 x 20 inches, 4 to 5mm thick. Keep the edges square. Let it rest a couple minutes if it resists.
2. Cut triangles. Trim the edges clean. Mark 4-inch intervals along the long edge and cut long triangles with a 4-inch base and 8-inch height. You'll get about 12.
3. Stretch and notch. Gently stretch each triangle slightly longer. Cut a ½-inch notch in the center of the base. The notch helps the classic crescent curl.
4. Roll the croissants. Pull the base corners outward slightly, then roll from base to tip with gentle, even tension. Place tip-side down on parchment-lined pans so they can't unroll.

Tip: Light contact, not pressure. Crushing the layers seals them shut and kills the rise. And if it's your first batch, shape all twelve but freeze half before they proof. Bake six fresh now, stash six for another morning. No pressure to nail a full dozen at once.

Final Proof

Sourdough croissants proof longer than yeasted ones because there's no commercial yeast pushing them. This is the step that decides whether your butter stays put. Don't rush it.

1. Proof, loosely covered. Cover the shaped croissants loosely so they don't dry out, and proof at 75 to 78F (24 to 26C) for 3 to 5 hours. That's longer than yeasted croissants. With sourdough it can run past that if your starter or kitchen is cool. Read the croissant, not the clock.
2. The jiggle test. They're ready when noticeably larger, visibly layered along the cut sides, and they wobble softly like jello when you nudge the pan. If they feel dense or tight, give them more time.

Wait: PT4H

Tip: Do not proof above 78F (26C). Butter melts long before the dough structure sets, and once it melts into the dough the layers are already compromised.

Bake to Mahogany

As they bake, water in the butter turns to steam and separates the layers. A hot oven and a single egg wash give you the deep golden shine.

1. Preheat. Preheat the oven to 400F (205C) with the rack in the center position, a full 30 minutes ahead.
2. Egg wash. Whisk the egg with the milk. Using a soft pastry brush, gently paint only the top of each proofed croissant, going with the grain of the layers. Keep the brush off the exposed cut sides — hitting those layers glues them shut and kills the rise.
3. Bake. Bake 18 to 22 minutes, rotating halfway through. They should be deeply golden, almost mahogany at the high points, and visibly layered along the sides. A pale croissant is an underbaked croissant.
4. Cool. Cool on a rack at least 15 to 20 minutes. The interior is still setting. Cutting too early gives you a doughy center.

Tip: Bake one tray at a time if your oven runs uneven. And a word for your first batch: if the honeycomb isn't picture-perfect, you still made real sourdough croissants, and they'll still taste like something worth the wait. Clean, even layers come with reps, not on day one.

Shaping Croissants

All from one sheet of laminated dough. Clean triangles, light even tension.

Classic Crescent (recommended)

The traditional curved shape.

1. Notch the base. Cut a ½-inch slit in the center of the triangle's wide base.
2. Stretch and roll. Stretch slightly longer, then roll base to tip with light tension, tip underneath.
3. Curve the ends. Bend the two ends toward each other into a crescent.

Straight (Modern Bakery Style)

Leave it straight rather than curving the ends. The look most modern bakeries use for all-butter croissants.

1. Roll without curving. Roll the same way but keep the croissant straight.

Pain au Chocolat

Cut rectangles instead of triangles.

1. Cut rectangles. Cut the sheet into rectangles roughly 3 x 5 inches.
2. Add chocolate and roll. Lay a chocolate baton near one short edge, fold over, add a second, and roll to enclose. Seam-side down.

Proof test: Ready croissants look puffy, show separated layers along the cut sides, and jiggle like jello when you nudge the pan. Sourdough takes longer to get there, so be patient.

Bake to Mahogany

Hot oven, single tray, deep golden finish.

Oven: 205°C / 400°F. Internal temperature when done: 93-96°C / 200-205°F.

Standard Oven, Parchment-Lined Sheet (recommended)

Center rack, one tray at a time for even browning.

Equipment: Sheet pan with parchment

1. Preheat. Preheat to 400F (205C), center rack, for a full 30 minutes.
2. Egg wash. With a soft pastry brush, paint a single light coat across only the tops, going with the grain of the layers and avoiding the exposed cut sides.
3. Bake. Bake 18 to 22 minutes, rotating halfway, until deep golden and almost mahogany at the high points.
4. Cool. Cool on a wire rack at least 15 to 20 minutes before eating.

Note: A few small butter spots on the pan are normal. Large pools mean underproofing, weak lamination, or butter that got too warm during rolling.

Storage

• Room temperature: Best the day they're baked. Up to 24 hours in a paper bag, though they soften fast.
• Refrigerated: Up to 5 days tightly wrapped. Bring to room temperature or warm briefly before serving.
• Frozen: Freeze after shaping (before proofing) or after baking. Up to 1 month.
• Refresh: Reheat at 350F (175C) for 5 to 7 minutes. Never microwave, it destroys the crisp layers.

Frequently Asked Questions

How is this different from the yeasted classic French croissant?

Same butter block, same three folds, same shape and bake. The difference is the leavening. A levain replaces the commercial yeast, so the dough ferments cooler and slower, the proof runs longer, and you get a gentle sourdough tang the yeasted version doesn't have.

How strong does my starter need to be?

Strong. There's no commercial yeast backing it up, so the levain does all the lifting. Feed your starter for a day or two beforehand until it reliably doubles or triples within 4 to 6 hours of feeding. A weak starter gives dense croissants no amount of extra proofing fully saves.

My sourdough croissants taste too sour. How do I make them milder?

Sourness builds during the long, cool fermentation. To soften the tang, keep both cold rests toward the shorter end of the 10-to-16-hour window, use a freshly ripe levain rather than one past peak, and let the final proof run a touch warmer and faster within the safe range under 78F.

Why is everything taking so much longer than the yeasted version?

That's expected. Wild yeast works slower than commercial yeast, and you're keeping the dough cool to protect the butter, which slows fermentation further. A proof that takes 2 hours for yeasted croissants can take 4 or 5 here. Watch the dough, not the clock.

Why did my butter leak out while baking?

Almost always underproofing, and it's a more common trap with sourdough because the slow proof tempts people to bake early. The dough hadn't built enough structure to trap the steam, so the butter ran. Proof until truly puffy and jiggly. The other cause is proofing above 78F, which melts the butter early.

Can I freeze them?

Yes, and it's a smart move for a first batch. Shape all twelve, then freeze half before they proof, wrapped tight, up to a month. Thaw in the fridge overnight, proof, and bake. You can also freeze the laminated dough after the third fold, up to 3 months. Freeze before baking rather than after for the best texture.

Nutrition

Per serving (1 croissant): 345 calories, 33g carbohydrates, 6g protein, 21g fat, 1g fiber, 280mg sodium. Makes 12 servings.