I really loved this book when I was small, although the details of the story are a bit hazy now...
I seem to remember that the heroine, Harriet, is about 8 years old, and helps her aunt run a cafe called the Cherry Pie. She also becomes an actress somehow along the way.
I've been looking for it for ages in all my usual charity shops and car boot fairs, but no luck yet. If you've got one for sale at a reasonable price, please get in touch!
There's an interesting mention of it on one of my favourite blogs http://www.middlebrowmagazine.co.uk but other than that none of my friends remembers it. If you should happen to stumble across it, snap it up and read it to all the 8+ children you know, it's a great story.