Watermelon marzipans - recipe from 'Three Little Halves'

I saw this recipe on my friend's blog: 

http://www.threelittlehalves.com/2013/08/the-family-heirlooms-watermelon.html

and wanted to give them a try, thinking they would be perfect for the upcoming holiday season. They are sweet and pretty small bites, green with the burst of red color! 
I have used pecans instead of the walnuts. 
Also, I froze few balls. When unexpected guests came, I took them out for few minutes to thaw and cut them into "watermelon slices" :). They still tasted fresh.

Bon appetit,

Miki