There's a really nice croissant place located in Bukchon along the road of Gye-Dong: Artisan Croissant. Gye-Dong, itself, is a fun and charming street filled with small shops, cafes and restaurants- a lot similar to how Garosu-gil was in the early years of its popularity.
Artisan Croissant has limited seating inside (around enough seats for two at a time), but the seats are usually available as most customers just take-out the croissants.
A variety of croissants, but I had gone along with the apple pie at the time. I also recommend the ham & cheese and chocolate croissants.
I had been watercoloring ginkgo leaves at the time of purchase.