The English meaning of the sentence...

Question

...[the cake] ”that she makes herself every year” implies that “she makes the cake for herself” (i.e. to eat herself). For the meaning in the exercise I would use the following: ”that she makes every year”.

As an aside, if someone asks “who made the cake?”, one might respond “she made it herself”. This results in a similar sounding sentence that does in fact mean “she made it”.

Accepted Answer

Hi Brian,
The expression 'faire soi-même' you would use for something that you have  made yourself ( i.e. you didn't buy it ) 
Je fais mes gâteaux moi-même = I make my own cakes 
doesn't imply that I eat all of them.

Elle fait ses vêtements elle-même = She makes her own clothes
Elle fait ses yaourts elle-même = She makes her own yogurts

For 'who made the cake? ' you could say 
Qui a fait ce gâteau? 
You might get the answer -
C'est moi qui l'ai fait ( moi-même) 
Hope this helps!

Answer

Bonjour Brian !
I understand your point, though I'd say both uses of "herself" are valid in English. Here, we specifically wish to emphasise the fact that she makes it herself, meaning it's home-made and not shop-bought for example. But to remove the ambiguity you rightly mentioned, we've now added a hint ("herself", i.e. home-made).
I hope that's helpful!
Bonne journée !

Answer

Hi Cécile, thanks for that.

My point was also that you shouldn’t use the English line ”that she makes herself every year” because this implies in English that “she makes the cake for herself” (i.e. to eat herself). I suggest that for the meaning intended in the exercise you should instead use the following text: ”that she makes every year”.