Can someone tell me where i can buy buche de noel in zurich please. Thanks.

Bûche de Noël

Sprüngli has them every year, they should have them in December and maybe January. Otherwise, you can make it yourself: thing sponge cake and butter cream will suffice.
Bon appétit!

Both Coop and Migros should have them in the chilled pastry cabinet and possibly with the normal cake display depending on what is used for the icing.