There are two Troitskiy Most restaurants near the Peter and Paul Fortress. This is the larger one. There's no English on the menu and very little spoken, and the workers didn't seem particularly keen to help me, but I guess tourists speaking no Russian would get annoying. They did point out what was vegan, so I can't really complain. The salads are on display, so I had a selection of those and they were fresh and tasty. The prices are cheap - meals for around 150 roubles.