Walked in around 11 am on Friday and the place looked like a deli with seating in the back. Went back around 1:00 and the space in front of the deli case was filled with two-tops, all occupied. I was a bit worried when they asked if we had a reservation (no) and then said they could seat us in the basement, but downstairs was actually very nice. Had to ask for the Italian menus (the English translations were mostly spot on).
They brought us a couple of tiny fresh cheeses dressed with olive oil and a basket of bread while we were reading the menus. Cheese was nice, breads were excellent (not surprising given their world-famous bakery half a block away).
It was a very warm day so we ordered a bunch of cold, picnic-type things. Mortadella and 36-month prosciutto (€12) and mozzarella di bufala with 28-month prosciutto di Parma (€24) were all good, but didn't compare with the best I had when I lived here in the mid-80s. Vintage 2012 tuna sott'olio (€15) was to me too intense for an appetizer, would make more sense to me in pasta all tonno.
A warm salad of seppie (€14) with avocado, baby green beans, cucumber, etc. was exquisite. I was surprised to have good avocados, those were unknown when I lived here.
Drank a bottle of nice Lambruschi Vermentino (€29) from the by-the-glass list. Coffee (€3) was a perfect Roman ristretto.
Service was correct and friendly. Pane €3 x 2, I'm not sure if that was per order (we had two) or if it's per person as usual here.
I might go back to try more cooked food and I'll definitely buy bread from their bakery. A couple of Italians at the next table said the carbonara is the best anywhere, but they weren't Roman so what do they know?