Updated: Dec 29, 2019
Get your tissue paper ready, because tears will be shed. I cried the first AND most recent time that I made sourdough croissants. The first time, they were tears of sadness and frustration. But yesterday, I wept tears of joy. Admiration for the shear beauty of the naturally leavened croissant I was cradling in my bare hands. The process is relatively straight forward, as I use the same fundamentals as when making a yeasted croissant, but there are a few key points I would like to point out that I find to be crucial to success in this process. See below these points before getting started.
1. Getting the bulk fermentation right. This dough needs time to bulk and build strength. Knowing when it is ready for fridge time after the initial rise is critical, as you want to make sure sufficient strength has developed before cooling it down.
2. Proof longer than you have ever proofed before. And I if it is too warm your butter will quickly leak out. Some temperatures that I have had success with for regular, yeasted croissants have been too warm for my sourdough croissants so I opt not to manipulate warmth but to let them proof for a long time at room temperature.
3. Be patient. Be very patient.
What You Need (For the levain build):
100 grams mature sourdough starter
150 grams bread flour
50 grams whole wheat flour
150 grams water
What You Need (For the croissant dough and lamination):
325 grams All Purpose Flour
50 grams Whole Spelt Flour
125 grams Bread Flour
50 grams Unsalted Butter (for the dough, room temperature)
8 grams salt
200 grams levain
100 grams Sugar
250 grams Milk
310 grams Unsalted Butter for lamination (any good quality unsalted butter from your grocery store will do. European style is preferable. If you're lucky and you can find the French blocks of extra dry, 84% fat, even better.)
The first thing you need to do is build the levain. Combine the ingredients from above and let sit, covered, at room temperature for 4 hours. Your levain will be ready when it increases in size and has a web-like consistency when pulled at.
The next step is mixing your dough. Combine everything into a bowl at once, including the levain and salt. Use your hands to squeeze it all together. Once you have a mixture that is incorporated, turn it out onto your work surface and knead. When I knead, I like to use the palm of your hand pushing forward and my fingers to pull it back into the center. Repeat this process until your dough has a nice smooth surface. This may take you about 10 minutes.
Once your dough has been kneaded, transfer to a clean bowl (add a little canola oil so that it doesn't stick). Leave the dough covered on your kitchen counter top for 6 hours. My kitchen is usually somewhere between 72-75f. Place your dough on a half sheet pan and flatten it until it is roughly the size of the pan. Transfer your dough to the freezer for 30 minutes and then to the fridge for another 30 minutes. I do this to make sure the dough is somewhat stiff - a yeasted croissant dough will have a stiff extensibility to it.
Now is a good time to make your lamination butter if you don't have access to buying a block that you can cut to size. If you have small packs of butter, simply flour your butter a bit and roll it out into a square that is half the size of your dough in the sheet pan. See my video below for my butter block roll out and lamination. You can also put your lamination butter in between two pieces of parchment paper and use your rolling pin to beat it down into a rectangle that is 9" long and 7" wide (don't pay too much attention to the measurements, they are just for guidance. Just beat it into a rectangle that looks big enough to fit into rolled out dough.) Put your butter block into the fridge until it's ready to use.
Once you are ready to laminate, you must make sure that you have the right consistency in your dough and butter block. Since we are using a rolling pin, it's important to know that you will warm the butter up much quicker than a baker using a sheeter (a sheeter is a machine that professional bakers use to rollout dough). You want your butter to be a bit bendable but not breakable. You should be able to push your finger slightly into it and make an indentation, but not get any butter stuck to your fingers.
Now it's time to begin laminating your dough. See the video below for a quick peek at my lamination. Although it is sped up, I did not cut anything out of the process.
Flour your work surface, transfer your rectangle of dough from the sheet pan and onto the work surface. Make sure that your butter block is the size of half of the rectangle. Place the butter block onto one half of the rectangle and fold it over like you are closing a book.
Use your rolling pin from the center to push gently down and start rolling your forward. Once you feel any resistance, flip it around and work the other side. You want to roll your dough out until it is about triple the original length. This is a rough estimation, and every dough will be different so try to learn how to use your senses. You may also want to widen it a little so that it does not end up too narrow.
Make sure you use flour on your work surface. It will be easier to dust off flour during your folds than deal with dough that got stuck on your counter and starts to tear. Flour is your friend and will prevent the dough from sticking. If you see any resistance or tearing, stop and let the dough rest in the fridge. If you see butter melting out or exploding out of the top or bottom, your butter was too warm. Cool it down in the fridge, but know that this imbalance in temperature may continue to disrupt the process. Don't throw your dough away now, though. Power through, and then try again after you've done the whole process.
Once your dough is about tripled in length, trim the edges so that you have a uniform rectangle. These rounded edges most likely do not have any butter in them and will mess with the layering if not trimmed away.
Fold the dough into thirds. This is called a single fold. Place your dough on your floured sheet pan and cool it down for 15 minutes in the freezer. Now, this is a tricky situation as the freezer can be detrimental to the consistency of your butter. If your butter gets too cold, it can harden and break apart. 15 minutes should be just enough time to get your dough back to a more stiff consistency without causing an imbalance with the butter consistency.
I find that with sourdough croissants it is not good enough to use just the fridge or no rest time in between folds. The dough always seems to fight with me, and the more you fight with your dough and work it, the more chances are you will warm it up too much. Warm dough during lamination is what will cause you to cry tears of frustration. Thus, using the freezer in short increments has been the key for me in this process.
After you've let it cool for 15 minutes in the freezer, repeat the elongation with the rolling pin. Aim for tripling in length. Trim the edges just like last time. We will now perform the double turn. Fold one corner of the dough in, just slightly. Fold the rest of the dough in towards that slight fold, and then close the whole thing like a book.
After you've completed this turn, let your dough rest in the freezer for another 15 minutes. After these 15 minutes, transfer the dough to the fridge for an additional 30 minutes of rest.
Once you've rested after your second fold, it is now time to roll out and shape your croissants. Flour your work surface and again elongate your dough. With sourdough croissants I like to roll it out just until the dough starts to resist on either side. You don't want to go to thin here. I find that a slightly thicker size to your dough can yield better layers for the naturally leavened croissant. Again, see the video for the roll out before the shaping.
Trim the edges so that you have a uniform rectangle. Use a pizza cutter or a large chefs knife to cut your preferred triangle size.
Once your triangles are cut, elongate them a bit with your hand by holding the base and running your fingers up the back side of it. Press the tip of the triangle into your work surface, and then roll them up by starting at the base of the triangle.
Once your croissants are rolled up it is time to proof them.
To proof a sourdough croissant: place your croissants on a sheet pan with parchment paper. I usually fit 6, at an angle, on a normal sized sheet pan at home. The key to proofing these is a lot of patience and a stable room temperature environment. These need a solid 12-15 hours proofing at room temperature, and so I find it best to do this overnight. If you leave your croissants uncovered, they will get dry, so what you can do is take a few plastic bags and create a covered environment around the sheet pan. It will look weird, but it works. Just makes sure the bags don't touch your dough and allow for growth.
You can tell your croissants are ready at first glance. You should, first and foremost, notice an increase in volume/size in them. In addition, you may notice a more clear definition of the layers. When you shake the trey, they will wobble a bit. Note, though, that if you've made yeasted croissants that there is usually a noticeable wobble and size increase. You may not see that here. If you see butter leakage, it means that it was too warm for the proof. Go ahead and move into the bake stage, but it might not end up pretty for ya.
Once your croissants are proofed and ready to go, preheat your oven to 375f. Make an egg wash by whisking together one egg, a splash of milk, and a pinch of salt. Use a brush to wash your croissants with this mixture and and bake straight through at 375f for about 16 minutes or until golden/dark brown depending on your preference. I opt to bake these guys a little dark.
Let your croissants cool, or not, and enjoy!