Fussy madam

Mitzi has now decided she only likes cashew nuts. If I hold up a piece of walnut, a hazelnut or an almond (all nuts she used to like) she just looks at me or she touches it with her tongue but won't take it. Only when I hold up a cashew will she take it. I say the name of the nut I am holding. The hazelnuts are blanched, so they can look a bit like a cashew but she knows the difference. 

Jane