On our recent small group tour to Peru, The Traveling Professor visited Cusco.  Here are three very good dining picks:

Incanto:  Located just off the Plaza Mayor, Incanto has something for everyone. Let's start with the starters:  I love the meatballs in a tasty tomato sauce or even the tomato-based quinoa soup.  Personally, I can make an entire meal out of the apps.  Pizzas are cooked in a wood-fired oven and the Pizza Cuatro Estaciones is stacked with tomatoes, mushrooms, prosiciutto and cheeses.  There are wide choices of pastas - at least 7 of them.  Go for the cavatelli with sausage.  No Peruvian menu is complete without Lomo Saltado but Incanto has more including risotto and great salads.  It is a larger restaurant so there is never a problem in finding a seat.

Cicciolina:  Go through the door on the side street, walk into the courtyard and up the stairs to the coolest dining spot in all of Cusco.  It's not a big place.  There is  dining room with tables and chairs but we always like to sit at the high-tops in the tapas bar.  I always start with a beer and order two or three tapas dishes.  It's hard to say what's on the menu since it changes regularly due to what is fresh from the market.  

Hanz Restaurant:  It's one of the most interesting places I have been in Cusco.  Owned by a Peruvian who waits on one of the six or seven tables, his Japanese wife cooks in the back.  They brew their own beer and serve up Japanese influenced Peruvian flair.  Here are some photos of the menus and pictures of our meal: https://photos.app.goo.gl/w6UVLGSmFIeFakD72.  By the way, Hanz is their dog (still in Japan).