(I would like to reassure vegetarians who by now have been taken by convulsions that other type of dishes are also available in Rome like artichokes and courgette flowers - see one of my previous posts. So don't feel disgusted and give up with the idea of eating in Rome!) .
The traditional ways of cooking those "delicacies" listed above are either stewed in tomato sauce or fried. I adore them when they are fried but probably because, as my grand-father used to say, "even a shoe sole would taste good if fried". Romans though don't fry simply offals. They fry almost anything!
Two revelations when I visited the Capitol last time: scamorzine fritte in mortadella and ricotta fritta.
The first ones are simply small chunks of scamorza (a stringy sheep cheese often smoked) wrapped in mortadella and then coated in a very light batter and fried. They had been previously fried and didn't need to be fried again when we order them - simply warmed up in the oven and "ecco!" ready to be slurped up in one bite! Divine.
The other ones are small balls of ricotta (half fresh and half stagionata) coated in the same batter and fried. I was told you can also use "smoked ricotta" to give it that extra dimensional flavour. Not to be missed! You can find them both almost anywhere but I would recommend Volpetti in Testaccio, the old abbatoir area of Rome where still now one can eat the best meat (and offals) of the city.
The second revelation was "trapizzini", something in between a tramezzino (soft bread triangular shape sandwich) and a pizza. The idea is to have a pizza dough triangular piece of bread which gets cut on one side and stuffed according to your choice - no vegetarian option here I'm afraid! We tried "salsa verde and tongue" (a sauce made of parsley, hence "green", olive oil, capers, anchovies and a touch of salt) and "coda alla vaccinara" (ox tail stewed in tomato sauce, chilli and black pepper).
The hole in the wall where you can try these funny little fellows is on the parallel road to the square where the main market in Testaccio takes place every day (which also happens to be the perfect place to buy artichokes, courgette flowers and green cauliflower - very unique to this area).
One thing that is sure and I can guarantee: you won't leave Rome hungry!