Buttermilk in Swedish.

So if you read my previous post, you will see the picture of the Red Velvet cake with Marshmallow frosting I made for Perry's birthday. The recipe called for Buttermilk, but I have NO IDEA was it is called in Swedish. I don't even know if it exists here.

I used whipping cream, and the cake was dry and dense.

I am assuming it may be called filmjölk, which I thought was like a sour yoghurt.

Does anyone know??? Can anyone tell me????

I NEED to KNOW!