It may have originated in Britain in the 17th century where it is also known as Trinity College cream. It is claimed that chef at Trinity College, Cambridge accidentally burnt a custard he had sprinkled with sugar and served it up as an new dish.
References
[1] Delia Smith's Complete Cookery Course by Delia Smith (BBC 1997) ISBN 0-563-36249-9 p.482
[2] Perfecting Crème Brûlée (Cook's Illustrated, Nov & Dec 2001) p.22