The cake I made came closest to the gingerbread cheesecake bars. The recipe was essentially the same, but with a few additions. Plums, obviously, but also some stem ginger to the gingerbread mix, and some lemon zest and juice to the cheesecake. I omitted the ground ginger from the cheesecake batter, as I wanted complete contrast of the two mixes. Also, instead of pouring the gingerbread batter in the cake tin, covering it with the cheesecake mix, then marbling the two, I put alternating spoonfuls of the batters in the tin and then swirled them up with a knife. I think my method would be easier, as the gingerbread batter is much heavier and denser than the cheesecake, so to try and swirl the gingerbread above and into the cheesecake seems rather difficult.
I have just a cold piece with a cup of tea , and I was very pleased- I really like the contrast between dark, heavy gingerbread and light, tangy cheesecake. I wouldn't go as far to say that the plums 'make' the dish, but they are a really nice addition and suit the flavours of the cake.
If you want to make this recipe, I used this one as a base, from the Oven Adventures blog, which looks great- I'll be pouring over it later. Add the zest of one lemon and one teaspoon of the juice to the cheesecake batter, and one ball of stem ginger, grated, plus a little of the syrup from the jar to the gingerbread. Omit the ground ginger from the cheesecake mix. See my notes above for mixing the two batters in the cake tin. Finally top with some sliced plums. I used 4 plums, each cut into four thick slices.