Soup is a pretty easy entree (or main for that matter), you can make that ahead of time and then just heat it up.

Risotto? If you have a massive pot that is. I say that because I always end up making enough for 5 when I'm trying to cook for 2 anyway.

How about apple or peach crumble for dessert? Oh, Cai said that. You can buy pie fruit from the supermarket. And if you serve it with custard or ice-cream you can make the crumble go further.