This is a long shot...
I was in Rome earlier this year with a small group. We tried to go to a restaurant we had found at the top of the Spanish Steps but they were closed for a private function. I'm heading back in November so I'm hoping we can try again. However, silly me, lost the business card for the place so now I have no idea what it was called.
Basically, if you're looking from the top of the stairs down (in front of the church), it's at the top along the right with a killer patio and a more intimate downstairs.
If this makes any sense at all, help is appreciated! :)