Up on Namsan about five minutes walk from the Hyatt Hotel is a curious cafe/restaurant called "The Classic HwaSooMok". It's a strange and rather pricey place with odd art on the walls and a lovely garden to relax in. The ravioli was expensive (20,000 won or so) but was surprisingly delicious. Packed with ricotta, onion and spinach, these tasty little parcels of Italian joy were enough to put a smile on my face.
You can visit their website here and find a map to their place here.