Combine the broth, pastina and salt in a large pot and bring to a gentle boil over medium-high heat, stirring occasionally
Continue to cook and stir until the pasta is al dente and there is a small amount of liquid left in the pan, about 5 minutes
Remove from the heat and immediately add the butter, Parmesan, beaten egg, and lots of black pepper
Stir very quickly so that the heat from the pasta doesn't begin to cook the egg, to incorporate the egg into the warm pasta and melt the cheese
Serve in bowls with extra Parmesan and a healthy glug of olive oil
