80's fantasy movie about "tree of youth"
When I was little, I remember watching a movie that was made in the 80's about a boy/girl who goes through his/her mirror to this magical land with puppet creatures. They go to this castle or something where there is a very mean queen who has a tree that produces fruit that makes her stay young forever. The boy/girl steals some of the fruit to take back home for his/her grandmother to keep her young. When the boy/girl steps back into his/her mirror, they drop the fruit and it disappears. Any ideas of what this movie is? I have been looking for 20 years. Thanks!
