I visited the enormous new Peruvian sensation La Mar over the weekend, mostly because I  wanted to try their Pisco Sours.  They were terrific. I  don't know what they do for the egg-white foam on the top, which was as firm and lasting as a good brick wall (our server said they use  "pasteurized egg whites"), but the entire drink was delicious. It had  that lovely limey-floral high tone of a good Pisco Sour, the  requisite topping of bitters, and went down incredibly smoothly. I highly recommend.