Found this place with a bit of wandering around. The map here is wrong and the streets are kind of confusing for us. Heading north on Okeansky Street (from, for example, Central Plaza by the water), you will come to Pokrowski Park & Cathedral on the right. Continue on the street for about five more minutes, the restaurant will be on the left. You can see a sign in roman letters saying "vegetarian cuisine."
Cons: No English menu