please help find forgotton childrens story

[hsbart]

hello, I'm trying to find the name of a book i remember from childhood. I read it in the early 80's but it could be older, i think it was a picture book with a little bit of text.
The story followed two children, I think they were brother and sister or perhaps two sisters(i'm sure they both had blonde hair!) they were staying/living in a house in the countryside. They discover a secret world the entrance to which was behind a tree i think, or maybe in the side of a hill. They visited the people from this other world often and I'm sure that they were fed pancakes!
I know this is a long shot because there isn't much to go on. I must have been very young when i read it and i can only remember glimpses of it.Can anyone help?
Thank you

 

[curlysue0819]

By any chance was the person they visited a 20s era actress? It sounds similar to a story that I read, but mine may have been geared to 8-10 yr olds. I think the actress' name may have been Tallulah.