La Nduja  is located in the neighborhood of San Lorenzo. It serves Italian cuisines and specializes in authentic Calabrian  dishes. Whether it bread, meat, wine or desserts; the food cooked here is mouth watering. The service is warm, welcoming and professional and the diners are treated with utmost courtesy and respect.

 (Source: La'Nduja - Roma - Cucina italiana o pizza)

Here are a couple of  glowing reviews from a diners

Excellent restaurant, excellent reception seems to be in family. The waiters are courteous and friendly under the supervision of Francis, the owner, who makes you feel like a king! Appetizers, main courses, sweets and refined superlatives. The presentation of the dishes and 'elegant and well as the stomach fills the eyes. Youthful, sparkling and clean. Do not forget the fries and pizza, cooked in the best tradition of wood-fired oven, with first quality ingredients. ' Excellent cellar wines and spirits, with the excellent Berta Grappa (which serve only the finest restaurants). Truly unique, excellent, distinguished, superb restaurant in Rome. Fair prices with quality 'high. I'll be back there 'and would recommend anyone to go there.

 (Source: TripAdvisor)

The nduja is a place where reigns the courtesy, quality, service and friendly staff! The nduja is a typical product of Calabria where we can eat here, taste and savor the typical products of Calabria, but not only .. We come often in preference to eat cheese and pepper in the form of cheese, great thread and the various meat smoking on the plates! You can taste all the wines of excellent quality and finish as much sin of gluttony ..... excellent desserts on their own production! Rita Leonard and Giorgia.

 (Source: TripAdvisor)

 Meat sauce on spaghetti (Source: thisisbossi)

Address:Piazza S.M.Consolatrice, 1-4 (zona Casalbertone), 00159 Rome, Italy

Phone: 064370025

Price range: $22 - $37

Feeling homesick? Then visit L'Invincibile Ristorante Trastevere. L'Invincibile's  homely atmosphere makes you feel at home. The homemade food cooked using local and seasonal ingredients  are delicious. Everything  served here, starting from the bread is homemade. The food is simple, flavorful and fresh. Moreover the service is delightful ,warm and friendly.

Google Translate (Source: Google Translate)

Here is a snippet

With fewer than 10 tables and a repertoire of homemade local favorites, L'Invincibile Trastevere restaurant is a true Roman trattoria - a foodie 'find'. Housed in the charming medieval area of Trastevere, it's one for you if you like boutique off the beaten track restaurants. A popular husband and wife team run the casa; her front of house, him in the kitchen rustling up L'Invincibile Trastevere specialties- simple, well-made and beautiful takes on local dishes made super-fresh with locally-sourced produce. The menu changes every month and is as good value as the wonderful wines, so there's always a reason to go back. L'Invincibile Trastevere is often fully booked; reserve your table well in advance.

 (Source: toptable.com)

Check out this review

Super restaurant in Trastevere area of Rome. Busy, so make sure to book in advance. We visited on a recommendation and were not disappointed. Friendly waiting staff who went out of their way to cater for my fish & seafood allergies. Varied menu also catered for vegetarians - a million miles away from Rome's many poor quality tourist menus. The food was a cut above anything we had tasted elsewhere in Rome during our visit. Desserts to die for - hazelnut praline with doughnut biscotti and a warm chocolate torte...simply divine! Extremely reasonably priced considering the high standard of food. Slightly lacking in atmosphere but the warmth of the staff added a warmth to the venue. Highly recommended!

 (Source:TripAdvisor)

Toasted Sandwich with King River Gold Washed-Rind Cheese (Source: avlxyz)

Address:Via degli Stefaneschi 3/5/7 | Piazza G. G. Belli, 00153 Rome, Italy

Phone: +39 3890382443

Hours
Closed on Monday
Open for lunch on Friday, Saturday and Sunday
Open on weekdays upon reservation

Price range: $13 - $66

Foe reservations click here

Al Duello is a relatively new restaurant located near Pantheon. This family run restaurant specializes in serving local cuisines. The food is excellent possessing unique flavors and tastes. The atmosphere is nice and the service was energetic, attentive ,polite and friendly.  Specialties include the 7 course prix fixe , 5 course menu and chocolate souffle.

 (Source:WhereTraveler, WhereTraveller)

Here is a snippet

Named after Caravaggio's duel in which he accidentally stabbed and killed his friend Ranuccio, this hearty trattoria commemorates the wrathful painter's wrongdoings. Try the Caravaggio artichokes, or order a plate of typical pasta, like carbonara or amatriciana. All is prepared with care, following tradition and paying attention to ingredient quality. Sophisticated wine selection

 (Source: WhereTraveler, WhereTraveller)

You might find this review interesting

We had an excellent dinner here on the last night of our honeymoon. We got the chef special that includes 7 courses, all chosen by the chef. Everything we tried was excellent and the prices were not bad. The Gnocchi was the best I've ever had and the chocolate souffle was absolutely incredible. Our waitress, the only one for the whole restaurant, was very attentive and one of the most cheerful people we met in Rome. Her husband is the chef. We would definitely recommend this small amazing restaurant for a nice dinner in Rome.

 (Source: TripAdvisor)

Chocolate Souffle (Source: The Marmot)

Address: Vicolo della Vaccarella, 11, 00186 Rome, Italy

Phone: +39 ( 06 6873348)

Hours: Monday-Saturday :19:00-23:30

Price range: $15 - $44

For reservations click here