This indispensable
bulb, used all over the world, varies from country to country and from
season to season. Onions range from tiny red onions of pickling size to
those as large as grapefruit. As a result, when a large onion is
stipulated, it could mean different things to different people.
To
introduce some uniformity in judging the size of onions, here is a guide.
A large onion is one that weights over 250g (8 oz); a medium onion is
about 125g (4 oz); a small onion weights in around 60g (2 oz). Weigh
some onions to get an idea of the sizes and it will save you much
deliberation.
Flavor and pungency also vary tremendously, but your discretion and
judgment as a cook to tell you when to increase or decrease the quantity
is expected. The small purple shallots so widely used in Asian countries
are not easily available in Australia, so recipes have been tested using
the common white or brown onion. If you do get hold of some shallots, use
them by all means, but in a smaller quantity than onion, and be sure to
cook them very carefully and not let them burn.
Spring onions are also useful in Oriental food and usually both white
and green parts go into the recipe unless otherwise stated. Strangely, in
Australia the spring onion is called a shallot; spring onions are also
known as green onions or scallions in the United States. Those best for
the purpose are straight, without a large, well developed bulb.