The grandmother is totally wrong in saying those things and turning her against her sister, because she is making her into the favourite.
This kind of behaviour should not be pushed on her at home / grandparents because there is too much of this at school.
Stand your ground dad, apologise if...
If you haven't tried it, don't knock it. Depending on what type of Hot Cross Bun you put this great combination on, I wouldn't use a chocolate chip bun, it would be great.
Go for it Larry, whatever turns you on, man.