This is a must in Moscow and Saint Petersburg (and in Kiev).
It is a luxurious shop like a palace, with enormous lamps and statues. They belonged to the family Eliseevky, and after the October Revolution were confiscated by the soviets.
In Saint Petersburg it is located in Nevsky Prospekt 56.
All the goods inside the shop are of first quality (but also “first prices”). You will find food from the five continents.