Since it was in Hongdae we ate dinner in Sinchon first, then took the subway to the Hongdae station and then walked. The good thing about this whole thing was that this was that this was the first place I'd found online that actually existed, the bad part was that it sucked.
Out of the six advertised kinds of cakes, they only had about two slices of carrot cake and three slices of honey milk tea cake (I mean I get it, it was towards the end of the day but they were still open for two hours so...). Arianne wanted the milk tea and this was her thing so that's what she got. It was also, coincidentally, the cheapest on the menu at the still exorbitant ₩7000 per slice (the more expensive ones went up to around ₩8500). Arianne and I switch off on who pays for things, and it was my turn, so I paid and we got our piece of cake.
It tasted fine I guess. I mean it didn't taste bad but it didn't taste good either. It was far too airy and crushed down to nearly half its height when forking off pieces. Even Arianne didn't like it, and ultimately it took us less than three minutes to eat it. We sat around for a while mooching off their wifi and then we just left.
All in all it was a massive waste of time and money and I'm inordinately depressed that I blew nearly seven dollars on a really subpar piece of cake. To be honest I think any premade cake from Weis would have been better.
**UPDATE (12/16): In the subsequent time I have quite quickly realized that you can get cake at any number of local dessert cafes, regular cafes, cat cafes, basically literally any kind of cafe, and for much better prices too, thus rendering this trip a big waste of both time and money.