The Art of French Pastry

huge quantities of dough
by hand in a big vat called
a pétrin (pétrir means “to
knead”). It’s an amazing
exercise for your fingers,
arms, and forearms, and
my father’s were incredibly
strong. He had to stir the
rocher batter quickly or
the heat would fry the egg
whites (we use a double
boiler for that reason), and
he had to stir for a long