One of the Best in Helsinki.
As somebody who has lived in Helsinki, I've sampled a variety of the fare they offer--Kasakka is the best. The environment is like Russia at the turn of the century--pictures, tassles, and (if you're lucky) live music performers adorn each dining room.
The servers are friendly and witty. They are eager to make your stay fantastic, and got to the point of knowing my family well enough to brink us drinks as soon as we sat down.
However, setting all of that aside, the food is wonderful. The food is indescribable--from the soups, to the free-flowing caviar, and the extensive and unusual meat menu (often including reindeer and bear), each bite is better than the one before. Also, they have a fantastic side dish of garlic potatoes.
Generally, a very, very fun experience, especially to go with a group. Be sure to try as many things as you can. One of my favorite restaurants on Earth.