From Longman Dictionary of Contemporary Englishthe jewel in the crownthe jewel in the crownBESTthe best or most valuable part of something Puddings are the jewel in the crown of British cookery. → crown jewel → jewel
Examples from the Corpus
the jewel in the crown• The Wine Rack is the jewel in the crown of a 1,000-strong chain of shops which have been reorganised into two groups.• Though, the jewel in the crown for the whole of the area must be Blenheim Palace. 