One evening after seeing a brilliant Sleeping Beauty in the Mariinsky Theatre (formerly the Kirov Ballet) we dined at Dvorianskoe Gnezdo. This fabulous restaurant is located in the tea pavillon of the Yusupov Palace which is the site of Rasputin's assassination (arsenic-laced cholcolate cakes, then bullets, beatings, and finally drowning - must have been a chowhound).
The restaurant aspires to serve food and drink of the very highest quality and achieves that in elegant surroundings which echo the prerevolutionary period with waiters dressed in natty frock coats, harpist, classical decorations and paintings etc. It could be naff but in fact is convincing and fun.
We started with a delicious smoked salmon amuse-guele, beluga caviar on the most exquisite blinis (washed down with quite a few shots of freezing vodka), pelmeny (dumplings) with sour cream and a delicate tomato and dill sauce *(I regret to have to confess that one of our party opted for the bear meat variety), creme du Barry (chicken cream soup), grilled veal chop, a baked apple and chocolate pudding. A great experience.
We also dined at the Davidov restaurant at the Hotel Astoria and this was also excellent with lashings of caviar, pelmeni, baked crab and very good Russian wine. Elegant surroundings and helpful and friendly staff.
One night we slummed it by hitting a few bars and in the hip-appearing Face Cafe (nab canal Griboedova)sampled an Orange Dog - lemon juice, vodka and about 8-10 drops of Tabasco - very refreshing! We ended in a restaurant/club called Korchma(69 nab canal Griboedova) and had some more drinks, ok food and fun dancing and joshing with the friendly young Russians. I highly recommend St Petersburg and in particular the early period paintings in the Russian Museum and of course the Old Masters (Rembrandt especially) in the Hermitage.