Start with the dough. Place the warm milk in a bowl and add the yeast. Allow it to sit in the bowl for a few minutes until frothy. Add the flour, sugar, salt and butter to the bowl of a stand mixer fitted with the paddle attachment. Mix on medium speed for 1–2 minutes, until the mixture is finely distributed into crumbs. Add the aquafaba to the milk mixture, then slowly pour into the bowl as the mixer runs. When the dough comes together, switch to the dough hook attachment and knead for another 5 minutes. Wrap the dough in plastic wrap so that it is sealed, but not too tightly, as it will begin rising in the fridge. Leave to rest in the fridge for 6–12 hours.

Prepare the Beurrage (butter). Spread a sheet of parchment paper over a large work surface that you can easily roll the dough out on later. Place the block of cold butter on top, and sandwich it between another sheet of parchment paper. Use a rolling pin to gently bash and flatten the butter. Using a sharp knife, trim the edges to form a smooth 6-inch (15 cm) square. Add the excess butter back on top, sandwich again between parchment paper and beat the butter into the square, so it is nice and even. Move to the next step ONLY when the beurrage has had at least 1 hour to collect itself in the fridge.

Sprinkle flour over your benchtop. Unwrap the chilled dough, then roll it out into an 8-inch (20 cm) square. Score a square the same size as the beurrage in the center of the dough, then use a dough scraper to cut lines from each corner of the square to the outer edge of the dough. Leaving the center square intact, roll out the dough edges until they are large enough to fold over the center square. Place the unwrapped cold butter block in the center and fold each of the edges over the top, securely sealing the butter payload inside. Flip the dough over. Press or lightly beat all along the length of the dough with a rolling pin to squash it down and secure the layers. Wrap in plastic wrap and return to the fridge for 1 hour.

Flour the benchtop again, ready to begin your first tour of the dough. You’ll need to complete three tours, each consisting of one letter fold. Unless your kitchen is really cold, completely chill the dough for 1 hour in the fridge or freezer between each tour, aiming to keep the dough at all times below 50°F (10°C). Use a pastry brush to dust excess flour from the pastry as you go, to keep an even dusting as you roll.

Working either away from or towards you – not side to side – begin by pressing the rolling pin along the length of the dough. Repeat by pressing down the spaces left between the rolling pin indentations to flatten the whole thing, which will evenly begin to lengthen the dough in one direction. Check that both sides of the dough are adequately floured, then roll the dough carefully back and forth to give you more space to complete a fold. The more precise and neat you are at forming this rectangle and performing the first fold, the better your internal structure will be.

Use a pastry brush to dust off excess flour, then give the dough a quarter turn so the long side is facing you. (If at any point the dough tears or butter is exposed, dust flour into the spot to ‘repair’ it, then return the dough to the fridge for at least 1 hour before proceeding.) Now perform the first letter fold. Fold the bottom third of the dough over, then fold the top third over this, as though you needed to fit the dough into an envelope. Again, you should still use a pastry brush to dust off excess flour! With the end of the rolling pin, tap lightly and evenly all over the top of the dough to secure the layers, completing the tour of the dough. Cover in plastic wrap and get the dough straight back in the fridge for at least 1 hour to cool back down.

Repeat steps 5 and 6 twice more to complete three full tours.

Complete a final dusting off of any excess flour, tap the top of the dough with the rolling pin to slightly lengthen, trim the very outer folded edges with a pizza cutter – and then the dough is finally ready … tomorrow! Cover in plastic wrap and refrigerate for at least 2 hours, or even overnight, as yet another test of your patience.

Return the dough to the bench. Press the rolling pin along the length of the dough. Repeat for the spaces left between. Throughout this process, generously pour flour over the dough several times, dusting off just about completely. Now roll the dough in all directions into about an 18 in × 24 in (45 cm × 60 cm) rectangle, ¼ in (5 mm) thick. Flip the dough regularly and re-flour as you do so, using your forearm to flip the dough over and guide it back to the benchtop when it is getting thin and large. Rest the dough for 5 minutes before proceeding.