Could it possibly have clear gelatin poured over it? Not even sure if that is doable but when I blow the pic up it looks as though it has a clear coating of something.
That's not a cake, it's glass.
The flowers and side swirl could be done in pulled sugar. I wonder if that top 'cake' could be done in blown sugar.
http://www.sweetandshiny.com/art-ivory-cake.htm Neat though!
you wont be able to get a cake looking like that glass object, all you can do is say to the customer that you will use that as inspiration, but it will not be exactly the same.
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