Cooking is simply the preparing of food.

It doesn’t necessarily require the application of heat.

If some one is being proud of a sandwich- let them be proud. We all start somewhere.

edit: to all the people downvoting me: https://www.dictionary.com/browse/cooking

1. the act of a person or thing that cooks.
2. the art or practice of preparing food; cookery.

https://www.merriam-webster.com/dictionary/cooking

1A) the act of preparing food for eating, especially by heating 1B) a manner of preparing food

To say that “cooking” requires heat is inaccurate. It’s the usual qualification, but is not necessary in a general sense.

and more to the point: If some one is proud of their sandwich, why would you take that from them? dick move. Even Gordon Fucking Ramsey had to start somewhere.