What's the name of the kids film, where 2 kids try to keep their grandma from getting old with magic cherries?

These 2 kids go through a magic closet or mirror, can't remember. They encounter this evil queen/witch who has eternal life because of these magic cherries (?) she keeps in a bell jar. The kids have to crawl through/over a sea of broken glass? Does this sound familiar? I think it also involved some cabbage patch like dolls. It's an 80s kids film. Anyway, the whole point is they think their grandma is getting too old so they are gonna steal the magic cherries and feed them to her. (... man... do kids watch bizarre stuff or what? lol)