Starter:3/4 cup sifted flour
1 Tablespoon yeast
5-6 Tablespoons warm water (approx 110 degrees F)
2 Tablespoons sugar
Dough:
1 3/4 cups sifted flour
2/3 cups whole milk, warm
1 1/2 tsp salt
1 cup (2 sticks) unsalted butter
dorure (egg yolk glaze) made from 1 egg yolk plus 1 Tablespoon whole milk
Step 1: Make the Starter...
To make the starter, stir together all the starter ingredients to form a small ball of soft dough, then submerge it in a tall container of warm water (110 degrees F). It will sit at the bottom for several minutes. When it pops up to the surface as shown in the second photo, it is ready to use.
Step 2: Continue making the Dough...
In a large bowl, stir together 1 cup of the flour, all of the warm milk and the salt. Scoop the starter dough out of the container of water and add to the bowl. Stir in the remaining 3/4 cup of flour. Crash on the counter top by with the aid of a bench scraper 30 times or so until the dough comes together and is smooth and soft, then flatten it into an 8 inch square, wrap in plastic and chill in refrigerator.
Step 3: Make the Butter Square...
Knead the butter with bare hands, smear it and scrape it with a bench scraper until uniform, shape it into a square, then wrap in plastic and chill.
Step 4: Rolling and Making Turns...
Place the butter square inside the dough diagonally as shown:
Wrap the dough around the butter square and pinch the edges to seal:
Roll the dough into a large rectangle 1/4 inch thick, occasionally lifting the dough with a bench scraper and sprinkling flour underneath to prevent sticking. In areas where butter bursts through, dust with flour. When finished rolling, fold as you would a business letter:
Turn the dough so that the open seam faces to the right just like a book: