The Art of French Pastry

yolk’s lecithin is a great
emulsifier that brings the
water and fat together,
while the white is a great
binder. Using only egg
yolks would work, but you
would have to use a lot of
them to make it set, and
that would give the tart an
eggy aftertaste. Using only
whole eggs would
introduce too much egg
white, which could make