On my tours to Italy, my favorite dining spots are as follows:

La Tagliata in Positano:  the scenery is stunning, the food is plentiful.  Organically grown on their own farm, enjoy fresh grilled veggies like eggplant, and fresh tomatoes.   The buffalo mozzarella wrapped in prosciutto is to die for.   The wine flows freely as the pasta is delivered to the table.  Out of this world.

Osteria dei Fabbri:  In the Jewish ghetto of Padua, pick out a seat from one of the community tables and get ready for authentic dishes like chick pea soup with fresh mushrooms or radicchio lasagna.   Website:  http://www.osteriadeifabbri.it/

On my tours to Paris, my favorite stop is:

La Pre Verre:  the 14.50 lunch special is the best deal in Paris.   I have had traditional French dishes like boudin noir and mideastern dishes as well.   Top-notch wines come with lunch as well as an appetizer (usually a salad) and coffee.  Website:  http://www.lepreverre.com/inde

On tours to Peru when passing through Lima, we ALWAYS stop here:

Restaurant Huaca Pucllana:  Set amongst ancient ruins, this restaurant is a hot-spot of emerging Peruvian cuisine.  Beef hearts may not be for everyone but a wide variety of appetizers as well as main courses like Amazon fish, beef, and pasta are always on the menu.  A top, top, top dining value at about $50 per person.  Website:  http://www.resthuacapucllana.com/es/

When on tour in Spain, we do like the Spaniards do:

Mercado de San Miguel:  In the heart of Madrid, it is the epicenter of tapas.   Enjoy those little hamburgers, meatballs, olives, sausage, and just about anything else you can think of.  Wash it down with classic Spanish wines.  Website:   http://www.resthuacapucllana.com/es/

For more information on Traveling Professor tours to Paris, Spain, Italy and Peru, see www.travelingprofessor.com