The following recipe, prepared by Chef Antonio Carluccio, appears on antonio-carluccio.co.uk.
“I include a recipe for this well-known dish because most people I know get it completely wrong, either adding milk or cream or letting the eggs become scrambled. This recipe is the real thing.
It was brought to Lazio from Umbria by coal men (carbonari), who came to sell charcoal to the Romans. Since then it has been adopted by the Romans and is famous worldwide.”