definitions: plain cooking

We had a delightful but oft-repeated entree today -- rice with chili beans. When I called it "plain food", my diners objected. Boo asked me to define "plain".

"Tried and true," I said.
"There is a difference between plain, and tried and true," said Boo.

***

So, what is plain cooking?

My diners said plain cooking is:

"Where the deer and the antelope play."

• 
  

"One vegetable and one salad on the plate."

• 
  

"Anything without salt added."

• 
  

"Something without color."

Do you agree?