Grilled Cheese Sims just want to eat, serve, and make grilled cheese sandwiches. They even want to influence other Sims to cook grilled cheese for them. Their lifetime want is to eat 200 grilled cheese sandwiches. With this want, don't expect your Sim to stay fit and trim! Their fears revolve around being rejected for talking about grilled cheese and burning grilled cheese.
When a Sim has this aspiration, they are able to cook grilled cheese anytime during the day, even for breakfast. They do not need to have the required cooking skills to make it. Just make sure to have a fire alarm installed.
In case all this talk about grilled cheese has caused you to want one, check out the grilled cheese recipes from About's Home Cooking Guide.