La Rambla is the old school cafe I recommend the most in Recoleta. La Biela gets all the attention but the quality at La Rambla cannot be beat.
This cafe with waiters dressed in black waistcoats that may have worked here for decades is pure Recoleta. Come for a coffee and people watch.
If you're hungry, come for lunch. La Rambla's famous steak sandwiches (lomitos) are the best in town.