Prima Donna is an aged cheese from the Netherlands. It has much in common taste-wise with the aged gouda (actually pronounced how-da) from the same region. This is no ordinary aged gouda however: in terms of taste I can only compare Prima Donna to a 10 year-old gouda I once had from DiBruno Bro's. The cheese really has a sweet butterscotch-like flavor that is emboldened thanks to the little crystals (crystallized casein I've been told) contained within. This is an archetypal snacking or stand-alone cheese thanks to its melt-in-your-mouthability.
Although I disagree with their calling this cheese less sharp than Holland Gouda, here is a nice picture and description by the Artisinal Cheese Center. Oh, and the price tag is higher than what I payed, so maybe mine was different - cheaper and better!