I would rather called this honeycomb "kueh" than "cake" ,cos the texture is "kueh" like (Chinese/Nonya steamed pastry) . This is the cake that we'll usually focus on the texture inside make sure it formed a honeycomb like texture for about 3/4 portion height.
Have been seeing these cakes around for awhile ,with a few recipe on hands with slightly different methods ,wasn't sure which one to try untill lately chance upon this clip
Is really not that complicated as what I've thought .
The crucial part is during preparing the caramel, be aware not the over-cooked the sugar cos it'll burnt with seconds delayed. Also be sure to add in boiling water into the cooked caramel.
If you could feel the soft & "springy" touch by hand after baked as first check , next is to slice & check if those honeycomb formed.