Hmmmm... people I know with that name pronounce it the other way.
They are Danish/American
Go figure
My belief that "Rassmussen" is pronounced "RASS mussin" (not "Rass MIEW sun") comes from living in southern Sweden forty years ago.
But my Scandinavian speaking skills are rusty, so I will try pinging a couple of FReepers who have lived there more recently.