Is there an edible plant that grows nearly everywhere in the world?

For school I'm designing a global vegetarian restaurant chain that only sources local food. For most of the menu, I want to make it based on the region and diversely based on what's available, but just as McDonald's has it's staple 'burger and fries' I'd like to have at least one item on my menu that could be at nearly every location and grow locally at those locations. Any ideas? Thanks in advance!Is there an edible plant that grows nearly everywhere in the world?
Yes, Onions. They can be found in almost all climates from sea level to mountainside.Is there an edible plant that grows nearly everywhere in the world?
Cow.Is there an edible plant that grows nearly everywhere in the world?
mushroom??? I dont know . . .
Onions