Time for an innocent joke!

Source: British Council - Learn English

Important note:

Hello folks!

 There is a pun on the word turnover. In the UK, there is a very popular sweet pastry called an apple turnover.  "Apple turnover" means "apple pie".
To understand the joke we need to recognize words, contexts, and sometimes other people's culture.

 The normal answer to the question: "How do you make an apple turnover?" First you need flour and eggs and sugar...
Do you get it now?

Now check the definition of turn over and understand the humor of the joke completely.
Enjoy your day! See you!!