El Fogon is one of my few "haunts" and it never disappoints. With great staff, nice cozy ambience and decor and an authentic Peruvian menu it's one of my faves.
Appetizer suggestions: Papa à la huaincaina - cold boiled potatoes in a creamy sauce (trust me, it's delicious); fried yuca - like french fries but slightly different and very tasty.
For dinner I usually go with either the tacu tacu con bistek (thinly sliced spiced steak with a delicious rice & bean patty) or the lomo saltado (strips of chicken or beef with onion, tomato and french fries and a side of rice).
The food isn't overly hot or spicy so it's compatible with a lot of palettes. If you're not big on hot, avoid the little garlic chili dip that comes with the complimentary bread.
Make sure you also try Inca Cola, a Peruvian pop that's like a cross between cream soda and Mountain Dew - ignore the horrific fluorescent green colour, it's actually really tasty.