Saying the porchetta sandwich from Roli Roti is good is like saying puppies are cute or soda has bubbles. The sandwich, made since 2006, is responsible for those snaking lines at the Ferry Building stretching past Gott's outdoor seating, and has ascended past the subjective analysis and into objective. If you like pork, the porchetta sandwich ($9.50, rotisserie cooked porchetta, caramelized onions, cress) is delicious. Fact.
The secret here is the skin and the truck. The skin acts as a barrier, sealing in all the fat and juices as it turns on the spit, resulting in meat that comes out tender, almost braised. This is a feat almost impossible to accomplish in an oven, where there's a high danger of overcooking the leaner meat without properly rendering the fat or crisping the skin. This is where the truck comes in: High BTUs and blazing large spits yield something exceptionally porky. In the process, the skin gets crisped to a luscious dark caramel color, denser and richer than chicharrones, with a snap more like brittle than potato chips. The mahogany skin, glistening with fat, gets distributed liberally, adding wonderfully salty pops of texture.
It's an accomplishment that owner Thomas Odermatt maintains better than anyone else, serving crisp skin with juicy meat in the 500 or so sandwiches staff members told me they sell during lunch.
If facing the always-long lunchtime line scares you, get there early and have the sandwich for brunch. It's porktastic at any time.