What went wrong with this bundt cake?
I did some googling as you suggested and found a few things:


One blog made the exact recipe and the top shows a deep "trench" between the outer rim and the middle chimney. As if the cake didn't rise well in the middle areas. Invert this, and the top may sink down on the platter, leaving a cavity like in your cake unless the cake is properly set.
Another blog shows beautiful pictures, but admits to have adjusted the recipe - less sugar, fewer egg yolks and cream. This brings it to standard pound cake ratios.


A pound cake is called pound cake for a reason: all main ingredients (sugar, fat, eggs, flour) come in equal parts, originally a pound (for very large cakes!).

The original one from the blog uses way more sugar and skimps a bit on the eggs, when looking at ca. 340g of flour and fat. Also, using butter and oil may be a problem - some pound cakes deal well with oil, others get a bit "mushy" in my experience. Replacing some eggs with cream (again, 180 ml is too much, as your too wet results show) can be done, but "weakens" the inner structure a bit, combined with extra sugar and oil it may be just too much. Looks like the baking powder either couldn't lift enough or the texture couldn't stabilize during baking and cooling.

You probably won't like this, but I suggest using ratios closer to a standard pound cake (less sugar, use only as much cream as needed to get the correct texture), then work from there towards the original until you find your personal threshold.