See the web listing for this apartment at Romanreference.com.
It's tough to tell the name of this restaurant - here's what I got off their menu: Antica Trattoria Dal 1923, Graziella e Alberto, da Spinosi a S. Pietro, Tirica Cucina Romana, via del Mascherino, 60-62-64, 06.6832.663. If nothing else, with the phone number you can call and get directions, hours, etc.
At the end of the Vatican tour, our guide Kenneth suggested we go to a restaurant very close by for good food at a good price. This turned out to be one of the best suggestions we had all trip. This is a small restaurant just outside of Vatican City. Clearly a mom-and-pop trattoria - mom runs the place with an iron hand, barking orders to pop who walks around with a shrugging "what can I do about it?" look on his face. We came in as a group and they just brought out food for us, and it was really good food. They started with a fresh salad chock full of mozzarella balls. I don't like salads but I couldn't keep away from the mozzarella - and everyone else raved about the salad. Then came plates of spinach ravioli. If I'd known it was spinach I wouldn't have gotten near it; I didn't know, so I ate it and I hate to admit that it was fantastic. LOL We'd also ordered pizzas and those were great as well. We had a couple carafes full of house wine - I wish I could find this wine here in the states. It was delicious. Sadly, it's just a house wine that probably isn't available more than 50 miles away from this restaurant.
We loved this place - for the rest of our trip we kept saying that we wanted to find a place like this one close by. This is everything you hope an Italian restaurant would be.