Puerto Sagua, an all-night Cuban diner, is a sort of refuge from the South Beach scene (and has been for 35 years, since long before there was a South Beach scene). Need a respite from all that sunshine and silicone? Cool off in Puerto Sagua and grab a cheap lunch. Need to fortify your stomach before a 4:00 a.m. drive home? Get a medianoche, or better yet, a bowl of excellent black bean soup. For $2.25, you get a cup of thick, garlicky flavor. The recipe is basic: onions, green peppers, garlic, cumin, and black pepper are added to the beans to make a tasty and filling appetizer. Or make it a meal, for $3.50 a bowl.