I cannot say enough good things about this place. A co-worker of mine is from Peru and he took me one day for a working lunch to this hole-in-the-wall hidden gem. The rotisserie chicken smelled heavenly, but as I am not one for chicken on a bone but always up to try new foods, I was greatly surprised to find a large menu of Peruvian favorites. I ordered the Lomo Saltado (steak with onions, peppers, tomatoes, rice and french fries) and have never looked back. He ordered the same and assured me that it was as good as anything his family makes at home! They offer a variety of sides and they don't skimp on the portions. The fried plantains are one of my favorites and they are always fried just right to the point of caramelization. The salchipapas (cut up hot dogs and french fries) is a Peruvian street food that is just comforting. Another friend of mine is married to a Peruvian and prides herself on her Huacaina sauce (a yellow sauce made with peppers and queso blanco) and she even gave theirs her stamp of approval (but of course it's not as good as hers :) This sauce is usually served over potatoes and although it is not on their menu they were happy to make it for us. I moved away from Frederick a few years ago, but I have driven hours to go back and to eat at Sardi's.