If you want to meet the kindest cheesemonger in Rome, visit Roberto at Antica Caciara in the 'you-must-cross-the-Tiber' Trastevere section of town. Stock up on Pecorino Romano (that amazing hard grating cheese used in the standard Roman fare Cacio/Pepe pasta) and sliced cured meats. And if you are still hungry, you can grab a bag of handmade pasta before Roberto kisses you 'buonasera'.
Like most places that serve truly amazing food without too much pomp and ceremony, Antica Caciara doesn´t look like much from the outside... a typical Roman looking deli with some bread in the window and a few salamis hanging in the doorway. But once you step inside the dimly lit cave the smells of cheese and general deliciousness come in waves and the queue of customers waiting to be served is an indication that this is no run-of-the-mill establishment.
Even if you end up leaving empty handed it´s worth the visit just to take in the feast of products displayed from floor to ceiling, but if you are in the mood for cheese then I have it on good authority that their ricotta is gorgeous and well worth the wait in line.