That is a the most surprising thing I ate (and liked) this summer. It was served on a very hot day in a cold soup and it was brilliant. Celery has wonderfully refreshing taste which works very well with sugar. I would have never thought of that, but it was there, on my plate, so I tried and loved it! To my surprise even my children like it! And they are picky.
So there you go, try this as an amuse bouche or desert, by itself or in a cold soup, for example in the watermelon gazpacho. Enjoy!
You will need an ice cream machine to make it though, I bought one just for this and am now planning other surprising flavors.