A good rule for custard is five eggs to a quart of milk, and a
tablespoonful of sugar to each egg, although a good plain custard can
be made with an egg for each cup of milk and four tablespoonfuls of
sugar to the quart. Creams and custards that are to be frozen must have
at least one-third more sugar than those which are not to undergo this
process.
In heating the milk for custard, do not let it quite boil before adding
the yolks. My plan, which has proved a safe one thus far, is to take
the scalding milk from the fire, and instead of pouring the beaten
eggs into it, to put a spoonful or two of the milk to _them_, beating
well all the while, adding more and more milk as I mix, until there is
no longer danger of sudden curdling. Then, return all to the fire and
boil gently until the mixture is of the right consistency. From ten to
fifteen minutes should thicken a quart. Stir constantly. A pinch of
soda added in hot weather will prevent the milk from curdling.
_Always boil milk and custard in a vessel set within another of boiling
water._ If you have not a custard or farina kettle, improvise one by
setting a tin pail inside of a pot of hot water, taking care it does
not float, also that the water is not so deep as to bubble over the
top. Custards are better and lighter if the yolks and whites are beaten
separately, the latter stirred in at the last.