I love walnut cakes! I had them in H mart a few years ago and I've fallen in love with them ever since. They have the texture of taiyaki, but molded into bite-sized bits with a cute walnut shape and stuffed full of paste. There's also a secret nut inside.
We arrived when they just opened, so they didn't have any red bean walnut cakes. So sad. Fortunately their other two flavors, mashed potato + almond/walnut were available. They're pretty cheaply priced, so we got a pack of 12 for $4.50! What a steal!
They pick them up by the handful from a big tray of freshly made walnut cakes. The people working inside are lovely and didn't rush us (even though we took forever to decide what to eat.) I haven't tried the other desserts yet but I'm pretty excited to eat them next time!