Complex sentence: In the rest of the Balkans, the top layer is often a custard: this is the version introduced in the UK by Elizabeth David's "Mediterranean Cookery" and where it remains as the "classic" presentation.
Split into simpler sentences: In the rest of the Balkans, the top layer is often a custard. This is the version which was introduced into the UK by Elizabeth David's "Mediterranean Cookery" and where it remains as the "classic" presentation.