This forum has always provided me with excellent restaurant recommendations.
Al pozzo etrusco di Fabrizio Grilli - On Piazza Rainieri at corner of vicolo ripa medici. It was so close to where we were staying so we tried it one night and liked it so much that we had our last dinner there. The service was very good and the wait staff so friendly and helpful. However, this was in 2019.....and then...Covid!! If you find it and try it, I hope it is still good and friendly.
At Geoff's suggestion we ate at Hostaria Postarula in 2019 and loved it. Unfortunately, it seems to be gone. Looked for it in 2021 ( and again in 2022) and the space was occupied by a restaurant with another name - Antica Fiascetteria Orvietana. We did not inquire if there was any relationship between the two but the name Hostaria Postarula is no more. A pity. We like Antico Bucchero. Trattoria del Moro Aronne has been a long time favorite, but the last couple of times we were there, some of the dishes didn't seem to live up to our past experience.
On my last visit to Orvieto, I dined at Ristorante L'Antica Rupe ( Vicolo Sant'Antonio, 2/A, 05018 Orvieto TR ). I was a great meal and I'd definitely return there on my next visit.
Last week, had lunch at Trattoria Aronne in the centre. It's also a Gastronomia. We had wild boar and Baccalà all'Orivetana, both very good. Prices were reasonable and staff friendly
In 2021:
Labirinto Di Adriano (our favorite during our 4 night stay, also includes a free underground part)
Trattoria la Palomba
Il Malandrino Bistrot
La Pergola
La Palomba.
Not fine dining but one of the best pizzas we've ever had was at
Pizzeria Antica Arte Napoletana