Inspired by someone mentioning macaroni cheese on another post...
Is there one food which as soon as you're reminded of its existence, you need to have ASAP?
Macaroni cheese for me (homemade). It's not my favourite food by far and I don't make it much, but perhaps that's why when I am reminded it exists I need to have it pretty soon.
Also, to a lesser extent, eggs. I eat them loads but if I haven't had an egg that day and I see someone cooking or eating a nice looking egg it really gets my egg sense going lol.