Mix the yeast, warm water, and first teaspoon of sugar in a small bowl. Leave aside for the yeast and sugar to dissolve and the yeast to foam up a little.
Measure out the other ingredients.
Heat the milk until tepid (either in the microwave or a saucepan), and dissolve in the salt and remaining sugar.
Place the flour in a large bowl.
Add the oil, yeast mixture and milk mixture to the flour.
Mix all the ingredients together using the rubber spatula, just until all the flour is incorporated.
Turn the dough out onto a floured surface, and let it rest a minute while you wash out the bowl.
Knead the dough eight to ten times only. The best way is as Julia Child does. It’s a little difficult to explain, but essentially involves smacking the dough on the counter (lots of fun if you are mad at someone) and removing it from the counter using the pastry scraper.
Place the dough back in the bowl and place the bowl in the plastic bag.
Leave the bowl at approximately 75°F/24°C for three hours, or until the dough has tripled in size.
After the dough has tripled in size, remove it gently from the bowl, pulling it away from the sides of the bowl with your fingertips.
Place the dough on a lightly floured board or countertop, and use your hands to press it out into a rectangle about 8 by 12 inches (20cm by 30cm).
Fold the dough rectangle in three, like a letter (fold the top third down, and then the bottom third up)
Place the dough letter back in the bowl, and the bowl back in the plastic bag.
Leave the dough to rise for another 1.5 hours, or until it has doubled in size. This second rise can be done overnight in the fridge.
Place the double-risen dough onto a plate and cover tightly with plastic wrap. Place the plate in the fridge while you prepare the butter.
Once the dough has doubled, it’s time to incorporate the butter.
Place the block of chilled butter on a chopping board.
Using the rolling pin, beat the butter down a little, till it is quite flat.
Use the heel of your hand to continue to spread the butter until it is smooth. You want the butter to stay cool, but spread easily.
Remove the dough from the fridge and place it on a lightly floured board or counter. Let it rest for a minute or two.
Spread the dough using your hands into a rectangle about 14 by 8 inches (35 cm by 20 cm).
Remove the butter from the board, and place it on the top half of the dough rectangle.
Spread the butter all across the top two-thirds of the dough rectangle, but keep it ¼ inch (6 mm) across from all the edges.
Fold the top third of the dough down, and the bottom third of the dough up.
Turn the dough package 90 degrees, so that the top flap is to your right (like a book).
Roll out the dough package (gently, so you don’t push the butter out of the dough) until it is again about 14 by 8 inches (35 cm by 20 cm).
Again, fold the top third down and the bottom third up.
Wrap the dough package in plastic wrap, and place it in the fridge for 2 hours.
After two hours have passed, take the dough out of the fridge and place it again on the lightly floured board or counter.
Tap the dough with the rolling pin, to deflate it a little.
Let the dough rest for 8 to 10 minutes.
Roll the dough package out till it is 14 by 8 inches.
Fold in three, as before.
Turn 90 degrees, and roll out again to 14 by 8 inches (35 cm by 20 cm).
Fold in three for the last time, wrap in plastic, and return the dough package to the fridge for two more hours (or overnight, with something heavy on top to stop it from rising).
It’s now time to cut the dough and shape the croissants.
First, lightly butter your baking sheet so that it is ready.
Take the dough out of the fridge and let it rest for ten minutes on the lightly floured board or counter.
Roll the dough out into a 20 by 5 inch rectangle (51 cm by 12½ cm).
Cut the dough into two rectangles, each 10 by 5 inches (25½ cm by 12½ cm)
Place one of the rectangles in the fridge, to keep the butter cold
Roll the second rectangle out until it is 15 by 5 inches (38 cm by 12½ cm).
Cut the rectangle into three squares, each 5 by 5 inches (12½ cm by 12½ cm)
Place two of the squares in the fridge
The remaining square may have shrunk up a little bit in the meantime. Roll it out again till it is nearly square
Cut the square diagonally into two triangles.
Stretch the triangle out a little, so it is not a right-angle triangle, but more of an isosceles.
Starting at the wide end, roll the triangle up towards the point, and curve into a crescent shape.
Place the unbaked croissant on the baking sheet.
Repeat the process with the remaining squares of dough, creating 12 croissants in total.
Leave the tray of croissants, covered lightly with plastic wrap, to rise for 1 hour.
Preheat the oven to very hot 475°F/240°C/gas mark 9.
Mix the egg with a teaspoon of water.
Spread the egg wash across the tops of the croissants.
Put the croissants in the oven for 12 to 15 minutes, until the tops are browned nicely.
Take the croissants out of the oven, and place them on a rack to cool for 10 minutes before serving.