In which novel does the protagonist write the word 'apple' over his diary entry, to hide it?

For all my adult life I have been convinced that it's Holden Caulfield, but I recently re-read 'The Catcher in the Rye' and it isn't. The writer in this book wants to blot out a previous entry in a diary, and discovers that writing apple, apple, apple masks the words. Which book is it?