Dilute the yeast with a little warm water and put with the flour, salt and sugar into a large mixing bowl.

Using a wooden spoon, slowly mix in a little water until the dough becomes pliable.

Tip the dough out onto a lightly floured surface and knead well until it feels elastic.

Put the dough back in the bowl and leave in the fridge for 1 hour.

Turn out the chilled dough onto your floured surface and roll it into a rectangle 60 x 30.

5 cm/24 x 12 inches.

Flatten the chilled butter into a rectangle about 1 cm/1⁄2 inch thick and lay it over two-thirds of the dough.

Bring the uncovered third of the dough into the centre, then fold the covered top third down, so that your dough is now in three layers.

Give the dough parcel a quarter turn so that the fold is on the right.

Return the dough to the fridge to chill for 1 hour.

Scatter some more flour over your table and roll out the dough to the same-sized rectangle as before.

Repeat the folding process, one side on top of the other, turn the dough again and place the dough back in the fridge for 1 hour.

You will need to repeat this whole process twice more before leaving the dough to rest, wrapped in clingfilm, overnight.

Line a baking tray.

Using a rolling pin, flatten the dough to 3 mm/1⁄8 inch thick and cut into 20.

5 x 20.

5 cm/8 x 8 inch squares.

Cut each square diagonally, making two triangles.

Lay the triangles on a lightly floured surface with the narrow points away from you, then roll each piece up from the edge nearest you towards the point, ending with the tip underneath.

Bend the ends round to make the traditional croissant shape.

Put the croissants on the baking tray and leave to rise for 11⁄2 hours.

Preheat the oven to 200°C

Preheat the oven to 200°C/400°F/gas mark 6.

Brush the croissants lightly with the eggwash and bake for 10–15 minutes until golden brown, then transfer to a wire rack to cool.