Step 1

First thing in the morning, feed your starter and leave it a warm spot to at least double in size. This should happen within 4 hours in 20-22°C temperature. If it takes longer than that, you may need to feed your starter again, to ensure it's active and not too acidic to make great croissants.

Step 2

Place the flour, salt, sugar, water, milk and active sourdough starter in a bowl of your stand mixer, fitted with a dough hook attachment. Turn the stand mixer on and knead for 5 minutes on medium speed until the dough comes together into a rough (rather stiff) ball. leave the dough to relax for 15 minutes.

Step 3

After 15 minutes, turn the stand mixer on again on medium speed, and start adding 50g of room temperature butter a little bit at a time. Keep the mixer running for around 8-10 minutes until the butter is fully incorporated and you have a smooth dough. It shouldn't be sticky.

Step 4

Shape a ball, slash the dough with a sharp knife in a cross on top of the dough (see photos in the text above, doing this will help you to roll it out into a square later) and place the dough in a lightly greased bowl. Cover and leave in a warm spot to bulk prove for approx. 4 hours. Ideally, you need a temperature of 21-23°C. If it is warmer, adjust the timing: your dough should rise 1.5 times. Place the dough in the fridge for another 3-4 hours to finish proving and double in size.

Step 5

Take the butter out of the fridge in advance to soften slightly. Place it on a large sheet of baking parchment, place another sheet of parchment on top. Using a rolling pin, gently bash to flatter the butter. Then fold the baking parchment under into a neat 18x18cm (7×7 in) square and roll the butter inside the parchment parcel into all the edged, aiming for the same thickness across (for detailed process photos, see text above). Enclosing the butter into the baking parchement square will help you get an even butter square with sharp edges. Still wrapped in the baking parchment, place the butter in the fridge to firm up.

Step 6

Take the dough out of the fridge and place it onto a floured worktop. Knock the air out with the bottom of your palm and roll it into a square around 28x28cm (11x11in). Try to make it even.

Step 7

Unwrap the butter (keep the baking parchment). Place the butter in the middle of the dough on the diagonal (see the photo above).

Step 8

Taking one side at a time, fold the edges of the dough into the middle creating a square envelope (see photos in the text above). Once you fold all four sides into the middle, pinch the edges together. You should now have a 20x20cm (8x8in) butter parcel. Wrap it in baking parchment and freeze on a flat surface for 10 minutes.

Step 9

First Fold: Take the parcel out of the freezer, unwrap and roll the parcel out into a rectangle that's around 50x20cm (20x8in). Make sure your dough isn't sticking to the worktop as you roll: you want the butter encased and the dough may tear if it sticks. Dust with flour if needed. Using a sharp knife or a pizza cutter, cut off any untidy short edges that don't have any butter in.

Step 10

Fold the rolled-out dough like a letter: from the short edge, hold 1/3 of the sheet into the middle, then take the opposite short edge and fold it over the first one. Wrap the dough in the baking parchment you kept the butter in, or cling film, and place in the freezer for 15 minutes, then transfer to the fridge for 1 hour.

Step 11

Second Fold: Take the dough out of the fridge and place it short edge in front of you. Roll the dough out to 50x20cm (20x8in) again. Fold the top third towards the centre and then bottom third over (just like before). Wrap and place the pastry in the freexer for 15 minutes, then fridge for 1 hour.

Step 12

Third Fold: Just like before, roll out the dough to 50x20cm (20x8in) rectangle. Fold like a letter, wrap and place in the fridge for a minimum of 6 hours (we leave it in the fridge overnight).

Step 13

On a lightly floured worktop, roll the pastry out into a 60x28cm (24x11in) rectangle, gently getting all the air out of the pastry. You don't want pockets of air to burst abruptly though, exposing the butter.

Step 14

Trim the sides. Cut 6 rectangles (approx. 10x28cm or 4x11in) using a sharp knife or a pizza cutter. I use a long ruler to make sure the rectangles are even width on both sides. Separate the rectangles. Use the ruler again to connect the opposite corners of the rectangle and cut across so you are left with two triangles. Once you've all your pastry, you should be left with 12 triangles. Trim the bottoms to create a straight edge.

Step 15

Make a little cut in the centre of the bottom of each triangle and stretch it out ever so slightly so the base of the triangle is wider. Roll the triangles tightly, from the bottom to the tip. Bend the ends of croissants to make a crescent shape, if you wish.

Step 16

Place your shaped croissants on two baking-parchment lined trays spaced out significantly, leaving plenty of space for them to rise. Cover lightly with cling film (you may oil the cling film first) and leave them in a warm spot (21-23°C) to proof for 4-5 hours. They should really puff up and the lamination should be clearly visible between layers.

Step 17

***If you live in a very dry climate or your kitchen is very cold: Boil a kettle of water and pour the water into an ovenproof dish. Place it in a cold oven to create steam and leave it shut for 5-10 minutes. The steam shouldn't make the oven too hot (keep it under 23°C - you don't want the butter to melt) but it should be warm and humid (this will prevent skin from forming on your croissants and hindering the proving process).

Step 18

Once proofed, take the trays and the water dish out of the oven. For freezing, stop here, and see the tips in the text above.

Step 19

Carefully take the cling film off. Place the croissants on the baking trays in the fridge to chill for 20 minutes.

Step 20

Preheat the oven to 190°C Fan.

Step 21

In a small bowl, whisk the egg yolk and milk. Using a pastry brush, very gently wash the chilled croissants with the mixture.

Step 22

Bake the croissants for around 20-25 minutes. Leave the croissants to cool for at least 15 minutes before digging in. They are best served within 2 hours from baking!