As well as gello di mellone (made with watermelon juice), Sicilians make gello do mandorla (made with almond milk), gello di cannella ( made with cinnamon and water) and gello di limone ( made with lemon juice).
It is thickened with corn flour and stirred like custard till it solidifies. There is nothing to it but surprisingly it turns out to be quite delicious.
This photo is of a gello di limone made by Barbera, wife of Corrado, the son of my cousin Franca. They all live in Ragusa, Sicily and it was one of the many things Barbara prepared for me when I was invited to dine with them (all the relatives go out of their way to cook Sicilian specialties for me when I visit them).
Now that you have the credentials, it is time for the recipe.