Fry (sauté) the onions gently in the butter for 5 minutes, stirring until
soft, then turn up the heat and fry for a further 4
minutes or so until the onions are golden brown,
stirring all the time.
Add the stock, rice and a
little salt and pepper, bring to the boil, cover and
simmer gently for 20 minutes.
Blend the corn flour
with the water. Stir into the soup and cook for 1
minute, stirring. Ladle into four flameproof soup
bowls.
Top each with a piece of toasted French bread
and cover with the cheese. Place until a hot grill
(broiler) until the cheese melts and bubbles. Serve
straight away.