determined  by  probing the interior    with    a
toothpick,  and is  a   matter  of  taste;  some
people  like    a   creamy  interior    that    still   clings
to  the toothpick,  others  prefer  a   more    fully
cooked  consistency,    which   clings  to  itself  and
leaves  the toothpick   clean.
Yolk    Foams:
Zabaglione  and Sabayons
Yolks   Can’t   Foam    Without Help    Beat    an
egg white   for two minutes and it  will    expand
eightfold   into    a   semisolid   foam.   Beat    an  egg
yolk    for ten minutes and you’ll  be  lucky   to
double  its volume. Yolks   are richer  in  protein
than    whites, and have    the added   advantage   of
emulsifying phospholipids   that    do  a   fine    job
of  coating fat droplets:   so  why can’t   they
stabilize   air bubbles and make    a   decent  foam?
One clue    is  what    happens when    you wash
out your    yolky   bowl:   the moment  you pour    in
some    water,  it  foams!  It  turns   out that    the
