Do not overstretch the dough. This will cause it to tear when resting and baking. Only stretch it as far as it will allow you to go.
Be sure to take it out of the fridge in time as the butter shouldn’t be harder than the dough.
5 On a clean, lightly floured surface, roll the dough out to a 40cm square. Put the butter square in the centre and fold the extending sides of the dough to enclose it. Pinch the seams to secure the butter in place.
6 Use the rolling pin to slightly flatten the square. Dust with the flour and carefully turn it over. Dust the opposite side and roll the square out to a
60 x 20cm rectangle.
7 Fold the rectangle in half lengthways. The dough should resemble a rough square. Turn the dough 90° so the seam faces towards you. Cover with a clean tea towel and refrigerate to rest, about 20 minutes. Remove from fridge and fold the square in half. Return to the fridge for another 20 minutes. Repeat once more.
8 Line a baking tray with baking paper. Set aside until needed. On a clean, lightly floured surface, roll the dough out to a 72 x 20cm rectangle. Cut the rectangle diagonally into 9 triangular pieces, each measuring 20 x 8cm.
9 Working with one triangle at a time,
lightly adhere the base of the triangle to the work surface by gently holding it in place with the palm of your hand. Using your other hand, pinch the point of the triangle between your forefinger and thumb, and gently stretch the dough out to 1½ times its original size. 10 Starting at the base of the croissant, tightly roll the triangle up into a conical shape. Tuck the point underneath the croissant – this will prevent it from unravelling. Place on the prepared baking tray. Repeat with the remaining triangles. Cover the croissants with a clean tea towel and set aside to rest in a warm, draught-free space until doubled in size, about 1 hour.
11 Preheat the oven to 200°C. Brush the croissants with the egg white.
Bake in the preheated oven for 10 minutes. Reduce the heat to 180°C and bake for another 10 minutes. Remove from oven and transfer the croissants to a cooling rack. Allow to cool completely before filling.
12 For the raspberry and cranberry pot de crème, place the 280ml full-cream milk in a medium saucepan. Bring to a simmer over medium heat.
13 While the milk is heating up, whisk the 55g castor sugar, eggs and cornflour together in a medium bowl until smooth. Slowly pour the warm milk into the mixture. Stir until well combined. Return the mixture to the still-warm saucepan and cook over medium-high heat, whisking continuously, until the mixture thickens slightly, about 2 – 3 minutes. Remove from heat and add the 95g unsalted butter. Whisk until thoroughly incorporated. Pour the mixture into a heatproof container and cover with cling film. Set aside until needed.
14 Place the frozen berries and 200g castor sugar in a medium saucepan. Bring to a boil over medium heat. Skim off any foam that might have formed on the surface. Continue to boil until the mixture reaches 105˚C on a sugar thermometer. If you don’t have a sugar thermometer, place a plate in the freezer for 15 minutes. Once chilled, remove from freezer and spoon a dollop of the coulis onto the plate. Leave for a few minutes to cool down. Create a well in the centre of the dollop – if the well holds its shape, the coulis is ready, if the mixture is
still too runny, continue to boil the mixture for another few minutes before testing again.
15 Once the coulis is ready, remove from heat and transfer to a blender. Blitz until smooth. Strain the mixture through a fine-mesh sieve into a jar. Set aside to cool completely.
16 Combine the berry coulis and filling together in a large bowl. Transfer the mixture to a large piping bag fitted with a Bismarck tip. Carefully fill each croissant by pressing the nozzle through the base of the croissant and piping the mixture to stuff it. Repeat with the remaining croissants.