Cornetti are the best way to end and start a night/day. There is literally no wrong moment for a cornetto. There is no doubt, though, about what the best moment for it is: when you are wandering the streets of San Lorenzo drunk.
Dolce Maniera is definitely the historical cornetto shop in Rome, so whenever you find a new one, you have to compare it to that one. Not many survive this test, but the Cornettaro di San Lorenzo definitely does: although brioches here are a little more expensive (it is still only 0.60 for each) the quality is top notch and they make some of the best “saccottini” (a rectangular cornetto) in town.
In case you don’t feel like walking all the way there you should not despair as this place is where nearly all the bars buy their brioches. Still, buying it directly at the shop, where you can see all the ovens and trays of cornettis ready to be eaten in the second room, just gives off a whole other vibe. Often I just want to hang out at San Lorenzo so I can go to this place.
I cannot stress enough how much a cornetto makes your whole night better. You have to trust me on this.