Actually guinea pig(cuy) is the traditional dish most associated with Peru, and indeed, you can find it in many parts of the Cusco(Tipon).
Restaurants: Normally in the restaurants in cusco many serve international cuisine but the quintas, basic local eating houses, serve mostly traditional Peruvian fare, full of spice and character in a typical Cusco ambience.
(Ponche de Leche con Pisco) Cusco can be cold in the evenings. But fear not, locals have come up with a cure. A hot glass of creamy Ponche de Leche with Pisco warms the parts other drinks cannot reach.
Some Restaurants in Cusco:
El Truco: Delicious but expensive traditional Cusco food in one of the city's flashiest restaurants, with fine beef and fish dishes. Music and Andean folk dancing is usually performed during the evenings, located in Plaza Regocijo 261 telephone 084-235295.
Café Ayllu: Serves one of the best breakfasts in Peru, including fruit, yogurt and toasted sandwiches, though it's not cheap. Centrally located with downstairs views across the plaza(Portal de Carnes 208), it's Cusco's most traditional meeting place and the service is fast.
Restaurant Mamala: Exceptionally great and very cheap set lunches in a nice ambience, conveniently located between San Blas and the Main Square(Choquechaca 509). Also serves decent pizzas and burgers. Telephone 084-246090.
Pacha Papa: A great, inexpensive restaurant set around an attractive courtyard, serving a range of hard-to-find Andean dishes, from a gulash de alpaca to the highly nutritious sopa de quinoa. Located Plaza San Blas 120 telephone 084-241318.
Dragon Dorado: A medium Chinese restaurant near the Plaza de Armas with good, ample portions and quick service; try the delicious kamlu wantan, enrollado, crispy meatballs in a tamarind sauce, located Plateros 373 telephone 084-245192.