A cafe overlooking the Grand Canal or St. Mark's Square on a warm summer afternoon begs for a cool confection. An icy watermelon granita, followed by an inky cup of espresso, and you know it' Venice in summer. "To me it is the best refreshment," Francesco insists. Watermelon is so Venetian. Refreshing slices of the fruit were a popular snack in the 18th century. In 1527 Pietro Aretino, a Roman visiting the city, remarked on the sale of melons in the market. "Twenty or 25 sailing boats choked with melons are lashed together to form a kind of island where people assess the quality of the melons by sniffing them and weighing them."
Puree the watermelon in a food processor, then force it through a sieve.
Mix the watermelon juice with the lemon juice and sugar to taste, mixing well to dissolve the sugar.
Spread the mixture into a metal cake pan and place in the freezer.
When it becomes slushy mix it up, then continue to freeze it, mixing it again as it begins to harden, about every 30 minutes, for about 4 hours; serve in goblets.