I guess the question is how realistic does she want it to be. If she just wants a game that revolves around baking cakes then you might try Cake Mania. It's a fairly popular time managment game that involves running a bake shop and baking custom cakes for different clients. It was in fact popular enough that it spawned at least 2 sequels. I still see women playing it from time to time. It's not especially realistic though.
You can find the link to the first one at http://www.sandlotgames.com/w5/cake_mania.html and I believe it may be free. If she likes it you could try one of the sequels, which may be a bit better.