Mix the yeast, warm water, and first teaspoon of sugar in a small bowl. Set aside for the yeast and sugar to dissolve and the yeast to foam up a little.
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 8 to 10 times. Place the dough back in the bowl, and cover tightly with plastic wrap. 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 roll it out into a rectangle about 8 by 12 inches. Fold the dough rectangle in three, like a letter — fold the top third down, and then the bottom third up.
Wrap the dough in plastic wrap and place on a cookie sheet 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 stick of chilled butter on a silpat (silicone mat). Using a rolling pin, beat the butter down until it is quite flat. Use the heel of your hand or a offset spatula to spread the butter until it is smooth and measures 10 by 8 inches.
Remove the dough from the fridge and place it on a lightly floured board or counter. Let it rest for a minute or two.
Roll the dough into a rectangle about 15 by 8 inches. Remove the butter from the silpat, and place it on the top half of the dough rectangle. Fold the bottom third of the dough up and the top third of the dough down. Turn the dough package 90° 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 15 by 8 inches.
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.
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 15 by 8 inches. Fold in three, as before. Turn 90°, and roll out again to 15 by 8 inches. 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).