Good take-away near Colosseum?

I have no specific suggestion to offer, but except for one seriously inferior meal in Arezzo, the only less-than-good food I had during a 2-month trip to Italy last year was takeway pre-cooked pizza, the type cut from a large sheet. Avoid that if you can. I found it no better than something similar from a US mall food court (shudder).

There is usually a food truck or two parked across the street, outside of the subway entrance.